FCC ID: AZ492FT4848 VRS 750- Vehicular Repeater System

 

VRS 750 Vehicular Repeater System Detailed Service Manual 1 Foreword The information contained in this manual relates to the VRS750 Vehicular Repeater System, unless otherwise specied. This manual provides sufcient information to enable service shop personnel to troubleshoot and repair the VRS750 to the component level. Safety Information Before operating the VRS750, please read the User Safety, Training, and General Information section in the front of this manual. Manual Revisions Changes which occur after this manual is printed are described in FMRs. These FMRs provide complete information on changes, including pertinent parts list data. Computer Software Copyrights The Motorola products described in this manual may include copyrighted Motorola computer programs stored in semiconductor memories or other media. Laws in the United States and other countries preserve for Motorola certain exclusive rights for copyrighted computer programs, including, but not limited to, the exclusive right to copy or reproduce in any form the copyrighted computer program. Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this manual may not be copied, reproduced, modied, reverse-engineered, or distributed in any manner without the express written permission of Motorola. Furthermore, the purchase of Motorola products shall not be deemed to grant either directly or by implication, estoppel, or otherwise, any license under the copyrights, patents or patent applications of Motorola, except for the normal non-exclusive license to use that arises by operation of law in the sale of a product. 2 Table of Contents Foreword . inside front cover User Safety, Training, and General Information . iii Safe Handling of CMOS Integrated-Circuit Devices . vi Model Chart for the VRS750 . vii VHF VRS750 Performance Specifications . viii UHF VRS750 Performance Specifications . viii Glossary of Terms. ix List of Abbreviations and Acronyms . x 1 - Introduction . 1 Description . 1 Ordering Information . 2 VRS Features . 3 Mutually-Exclusive Features . 3 2 - Installation . 5 VRS Installation . 5 Installation of the Mounting Trunnion . 6 VRS Antenna Installation . 7 VRS750 Programming . 7 3 - VRS Operation . 19 General . 19 Control Unit . 19 Vehicle Interface Ports. 20 VRS Access . 20 In-Car Monitor . 20 Mobile Audio Repeat . 21 4 - Operation of VRS Options . 23 Base Repeater . 23 Mobile Detector. 23 VRS Transmit PL Generator. 23 A

, Private Line, and Motorola are registered trademarks of Motorola Inc. Systems 9000, ASTRO, Spectra, Call Alert, Private Conversation, Single Tone, Digital Private-Line, and Slimnet are trademarks of Motorola Inc. Torx is a trademark of Camcar Div. of Textron, Inc. 2001, 2002 by Motorola Inc. Commercial, Government and Industrial Solutions Sector 8000 W. Sunrise Blvd., Ft. Lauderdale, FL 33322 Printed in U.S.A. 5/99. All Rights Reserved. 6881094C84 Detailed Service Manual i VRS Mode Steering . 23 Time-Out Timer. 26 VRS Single Tone. 26 VRS Mobile-TX Acknowledgment Tones (Conventional Only) . 27 Flashing Display . 27 Repeater PPI . 27 Quick-Key . 27 5 - Detailed VRS Operation . 29 Multi-VRS Operation . 29 Rptr PPIPortable Priority Interrupt . 34 TX PL Self-Clearing . 36 ICM Functions. 37 Acknowledgment Tones . 38 Non-Priority VRS Rules . 40 Emergency . 41 6 - Hardware Detailed Theory of Operation . 43 Power Regulation. 43 Bus Translation Circuitry . 43 Audio Routing Circuitry . 44 Single Tone Encoder . 45 Single Tone Decoder . 45 Boot Control Circuitry . 45 Program Sense . 46 Mode Configuration . 46 7 - Maintenance and Troubleshooting . 49 Troubleshooting Procedures . 49 Disassembly and Reassembly Procedures . 51 VRS Transceiver . 56 VRS Tuning and Alignment . 56 8 - Troubleshooting Charts . 67 List of Troubleshooting Charts . 67 9 - Diagrams and Parts Lists . 81 List of Diagrams and Parts Lists. 81 ii ii User Safety, Training, and General Information READ THIS IMPORTANT INFORMATION ON SAFE AND EFFICIENT OPERATION BEFORE INSTALL-

ING AND USING YOUR MOTOROLA MOBILE TWO-WAY RADIO IN A VEHICLE OR AS A CONTROL STATION. Compliance with RF Energy Exposure Standards Your Motorola two-way radio is designed and tested to comply with a number of national and international standards and guidelines (listed below) regarding human exposure to radio frequency electromagnetic energy. cycles of up to 50% talk-50% listen and should be used for occupational use only. measuring RF energy for compliance with the FCC exposure guidelines, your radio radiates measurable RF energy only while it is transmitting (during talking), not when it is receiving (listening) or in standby mode. This radio complies with the IEEE (FCC) and ICNIRP exposure limits at duty In terms of Your Motorola two-way radio complies with the following RF energy exposure standards and guidelines:

United States Federal Communications Commission, Code of Federal Regulations; 47CFR part 2 sub-

part J American National Standards Institute (ANSI) / Institute of Electrical and Electronic Engineers (IEEE) C95. 1-1992 Institute of Electrical and Electronic Engineers (IEEE) C95.1-1999 Edition International Commission on Non-Ionizing Radiation Protection (ICNIRP) 1998 Ministry of Health (Canada) Safety Code 6. Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the Frequency Range from 3 kHz to 300 GHz, 1999 Australian Communications Authority Radiocommunications (Electromagnetic Radiation - Human Exposure) Standard 1999 (applicable to wireless phones only) Operational Instructions and Training Guidelines To ensure optimal performance and compliance with the RF energy exposure limits in the above standards and guidelines, users should transmit no more than 50% of the time and always adhere to the following procedures:

Transmit and Receive To transmit (talk), push the Push-To-Talk (PTT) button; to receive, release the PTT button. Transmit only when people outside the vehicle are at least the minimum lateral distance away, as shown in Table 1, from a properly installed, externally-mounted antenna. Table 1 lists the minimum lateral distance for bystanders in an uncontrolled environment from the transmitting antenna at several different ranges of rated radio power for mobile radios installed in a vehicle. iii Table 1. Rated Power and Lateral Distance Rated Power of Vehicle-Installed Mobile Two-Way Radio Minimum Lateral Distance from Transmitting Antenna Less than 7 watts 7 to 15 watts 16 to 50 watts 51 to 110 watts 8 inches (20 centimeters) 1 foot (30 centimeters) 2 feet (60 centimeters) 3 feet (90 centimeters) Mobile Antennas Install antennas at the center of the roof or the center of the trunk deck. These mobile antenna installation guidelines are limited to metal body vehicles. The antenna installation must additionally be in accordance with:

a. The requirements of the antenna manufacturer/supplier b. Instructions in the Radio Installation Manual Use only Motorola approved supplied antenna or Motorola approved replacement antenna. Unauthorized antennas, modications, or attachments could damage the radio and may violate FCC regulations. Approved Accessories For a list of Motorola approved antennas see the appendix of this user manual. Fixed Site Antennas If mobile radio equipment is installed at a xed location and operated as a control station or as a xed unit, the antenna installation must comply with the following requirements in order to ensure optimal performance and compliance with the RF energy exposure limits in the above standards and guidelines. The antenna should be mounted outside the building on the roof or a tower if at all possible. As with all xed site antenna installations, it is the responsibility of the licensee to manage the site in accordance with applicable regulatory requirements and may require additional compliance actions such as site survey measurements, signage, and site access restrictions in order to insure that exposure limits are not exceeded. Electromagnetic Interference/Compatibility NOTE:

Nearly every electronic device is susceptible to electromagnetic interference (EMI) if inadequately shielded, designed or otherwise congured for electromagnetic compatibility. It may be necessary to conduct compatibility testing to determine if any electronic equipment used in or around vehicles or near xed antenna sites is sensitive to external RF energy and if any procedures need to be followed to eliminate or mitigate the potential for interaction between the radio transmitter and the equipment or device. Facilities turn off your radio in any facility To avoid electromagnetic interference and/or compatibility conicts, where posted notices instruct you to do so

. Hospitals or health care facilities may be using equipment that is sensitive to external RF energy. iv iv Vehicles To avoid possible interaction between the radio transmitter and any vehicle electronic control modules, for example, ABS, engine, or transmission controls, we recommend that the radio be installed by an experienced installer and that the following precautions be used when installing the radio:

1. Refer to any manufacturers instructions or other technical bulletins or recommendations on radio installation. 2. Before installing the radio, determine the location of the electronic control modules and their harnesses in the vehicle. 3. Route all radio wiring, including the antenna transmission line, as far away as possible from the electronic control units and associated wiring. Driver Safety Check the laws and regulations on the use of radios in the area where you drive. Always obey them. When using your radio while driving, please:

Give full attention to driving and to the road. Pull off the road and park before making or answering a call if driving conditions so require. Operational Warnings For Vehicles With an Air Bag Do not place a portable or mobile radio in the area over an air bag or in the air bag deployment area. Air bags inate with great force. If a radio is placed in the air bag deployment area and the air bag inates, the radio may be propelled with great force and cause serious injury to occupants of the vehicle. Potentially Explosive Atmospheres Turn off your radio prior to entering any area with a potentially explosive atmosphere. Sparks in a potentially explosive atmosphere can cause an explosion or re resulting in bodily injury or even death. The areas with potentially explosive atmospheres referred to above include fueling areas such as below decks on boats, fuel or chemical transfer or storage facilities, areas where the air contains chemicals or particles, such as grain, dust or metal powders, and any other area where you would normally be advised to turn off your vehicle engine. Areas with potentially explosive atmospheres are often but not always posted. Blasting Caps and Blasting Areas To avoid possible interference with blasting operations, turn off your radio when you are near electrical blasting caps, in a blasting area, or in areas posted: "Turn off two-way radio." Obey all signs and instructions. For radios installed in vehicles fuelled by liqueed petroleum gas, refer to the (U.S.) National Fire Protection Association standard, NFPA 58, for storage, handling, and/ or container information. For a copy of the LP-gas standard, NFPA 58, contact the National Fire Protection Association, One Battery Park, Quincy, MA. v Safe Handling of CMOS Integrated-Circuit Devices Many of the integrated-circuit (IC) devices used in communications equipment are of the CMOS (Complementary Metal Oxide Semiconductor) type. Because of their high open-circuit impedance, CMOS ICs are vulnerable to damage from static charges. Everyone involved in handling, shipping, and servicing them must be extremely careful not to expose them to such damage. CMOS ICs do have internal protection, but it is effective only against overvoltages in the hundreds of volts, such as those that could occur during normal operations. Overvoltages from static discharge can be in the thousands of volts. When a CMOS IC is installed in a system, the circuit elements in the system distribute static charges and load the CMOS circuits. This decreases the vulnerability of the ICs to static discharge, but improper handling will probably cause static damage even when the ICs are so installed. To avoid damaging CMOS ICs, take the following precautions when handling, shipping, and servicing them. 1. Before touching a circuit module, particularly after having moved around in the service area, touch both hands to a bare-metal, earth-grounded surface. This discharges any static charge you may have accumulated. NOTE:

Wear a conductive wrist strap (Motorola part number RSX-4015A) to minimize the buildup of static charges on your person while you are servicing CMOS equipment. When wearing a conductive wrist strap, be careful near sources of high voltage. By grounding you thoroughly, the wrist strap also increases the danger of lethal shock from accidental contact with such a source. 2. Whenever possible, avoid touching any electrically conductive parts of the circuit module with your hands. 3. Check the INSTALLATION and MAINTENANCE sections of this manual and the notes on the schematic to nd out whether or not you can insert or remove circuit modules with power applied to the unit, and act accordingly. 4. When servicing a circuit module, avoid carpeted areas, dry environments, and the wearing of static-generating clothing. 5. Be sure that all electrically powered test equipment is grounded. Attach the ground lead from the test equipment to the circuit module before connecting the test probe. Similarly, disconnect the test probe before removing the ground lead. 6. When you remove a circuit module from the system, lay It on a sheet of aluminum foil or other conductive surface connected to ground through 100,000 ohms of resistance. If the aluminum foil is connected directly to ground, you may get a shock if you touch it and another electrical circuit at the same time. 7. When soldering, be sure the soldering iron is grounded. 8. Before connecting jumpers, replacing circuit components, or touching CMOS pins (if this becomes necessary during the replacement of an integrated-circuit device), be sure to discharge any static buildup on your person

(see step 1, above). Because you can have a voltage difference across your body, you should use only one hand if you must touch the board wiring or any of the pins on the CMOS device. 9. When replacing a CMOS integrated-circuit device, leave the device in its metal rail container or conductive foam until you are ready to insert it into the pronged circuit module. 10. Connect any low-impedance test equipment, such as a pulse generator, to CMOS device inputs after you have applied power to the CMOS circuitry. Similarly, disconnect such low-impedance equipment before turning off the power. 11. Wrap CMOS modules in conductive material when transporting them from one area to another, even within the same room. Use wrapping material similar to that in which replacement modules are wrapped when they arrive from the factory. (You can also use aluminum foil.) Never use nonconductive material for packaging these modules. vi vi Model Chart for the VRS750 MODEL NUMBER DESCRIPTION P2080 P2081 P2082 VRS750 VHF (136-174 MHz) VRS750 UHF R1 (403-470 MHz) VRS750 UHF R2 (450-512 MHz) ITEM NUMBER DESCRIPTION X X X X X X X X X X X X X X 1 2 X X X X 1 1 2 2 X X X X X X X X X HHN4044*

HLN6855*

PLN7780 HLN6856*

PMLD4196 PMLE4242 PMLE4243 HKN6153 HKN6154 VRS750 Housing VRS750 Mounting Assembly VRS750 Controller Board XCVR Hardware VHF Transceiver UHF R1 Transceiver UHF R2 Transceiver Cable, Mobile-to-VRS Cable, Siren-to-VRS VRS750 Detailed Service Manual 6881094C84 2884606M01 Mini-UHF crimp connector YLN4480 HBN5086 3085031D02 NTN4056 NKN6460 TLN5277 RLN5394 3080384N02 VRS Pushbutton Packing Kit Cable, VRS Programming (accessory) Adapter, VRS Flash programming (accessory) y-cable kit for dual controlhead w/vrs (accessory) DC lter for excessive alternator whine (accessory) VRS750 Test Box (accessory) VRS750 ATE Cable (accessory) 1 2

= With option G334AC. Deletes HKN6153 cable.

= One item per 10 units.

*For piece part information, refer to the Exploded View section. For piece part information, refer to the Electrical Parts List section. vii VHF Performance Specications GENERAL TRANSMITTER RECEIVER Model P2080 (136-174 MHz) RF Power Out:

275 mW to 2 W tunable Intermodulation per EIA:

70 dB Number of Channels:

1, T1 = R1 Frequency:

Programmable, Synthesized Frequency Channel Channel Spacing:

12.5/20/25 kHz Operation Temp. Range:

-30C to +60C Primary Power:

13.8 VDC 20%, Negative Ground DC Current Drain (max):

120 mA Receive Spurious and Harmonic Emissions:

-36 dBm < 1 GHz

-30 dBm > 1 GHz Frequency Stability:

2.5 ppm @ 25 kHz 2.5 ppm @ 12.5 kHz Modulation Limiting (Max):

2.5 kHz @ 12.5 kHz 4.0 kHz @ 20 kHz 5.0 kHz @ 25 kHz Hum and Noise:

-40dBm @ 25 kHz

-35dBm @ 12.5 kHz Reference Sensitivity (typical):

0.28 V (-118dBm) at 12 dB SINAD Conducted Spurious Rejection:

70 dB Adjacent Channel Selectivity:

60 dB @ 12.5 kHz 70 dB @ 25/30 kHz 500 mA Transmit @ 275 mW Audio Response:

Squelch Operation:

1.10 A Transmit @ 2 W Private-Line required for repeater access Duty Cycle:

Intermittent per EIA at 275 mW PPI Sample Time:

16 ms Typical Singletone Encoder/Decoder:

Nominal 847.5 Hz

(from 6 dB/octave pre-emphasis, 300 to 3000 Hz) Audio Response (0.3-3 kHz):

+1 to -3 dB

+1, -3 dB Audio Distortion:

3% Typical @

Mobile Rated Audio*

Audio Distortion:

3% Typical @ 1 kHz, 60% maximum deviation Conducted Spurious Emissions:

FM Hum and Noise:

TX Attack Time:

Antenna Impedance:

-40 dB 32 ms Typical 50 ohms mini-uhf RX Attack Time:

-57 dBm <1 GHz

-47 dBm > 1 GHz 60 ms Typical FCC Identiers:

Industry Canada:

AZ492FT3802 (P2080) Antenna Connector:

*Typically 5 W in 8 ohms. Consult the product catalog sheets (ECAT Price Pages) for a list of disallowed frequencies. UHF Performance Specications GENERAL TRANSMITTER RECEIVER RF Power Out:

275 mW to 2 W tunable Intermodulation per EIA:

70 dB Hum and Noise:

-40dBm @ 25 kHz

-35dBm @ 12.5 kHz Reference Sensitivity (typical):

0.28 V (-118 dBm) at 12 dB SINAD Conducted Spurious Rejection:

70 dB Adjacent Channel Selectivity:

60 dB @ 12.5 kHz 70 dB @ 25/30 kHz Model P2081 (403-470 MHz) P2082 (450-512 MHz) Number of Channels:

1, T1 = R1 Spurious and Harmonic Emissions:

Frequency:

Programmable, Synthesized Frequency Channel Frequency Stability:

-36 dBm < 1 GHz

-30 dBm > 1 GHz 2.5 ppm @ 25 kHz 2.5 ppm @ 12.5 kHz Modulation Limiting (Max):

2.5 kHz @ 12.5 kHz 4.0 kHz @ 20 kHz 5.0 kHz @ 25 kHz Channel Spacing:

12.5/20/25 kHz Operation Temp. Range:

-30C to +60C Primary Power:

13.8 VDC 20%, Negative Ground DC Current Drain (max):

120 mA Receive Squelch Operation:

700 mA Transmit @ 275 mW 1.20 A Transmit @ 2 W Private-Line required for repeater access Audio Response:

(from 6 dB/octave pre-emphasis, 300 to 3000 Hz) Audio Response (0.3-3 kHz):

+1 to -3 dB

+1, -3 dB Audio Distortion:

3% Typical @

Mobile Rated Audio*

Audio Distortion:

3% Typical @ 1 kHz, 60% maximum deviation Conducted Spurious Emissions:

Duty Cycle:

Intermittent per EIA at 275 mW FM Hum and Noise:

PPI Sample Time:

16 ms Typical TX Attack Time:

Singletone Encoder/Decoder:

Nominal 847.5 Hz FCC Identiers:

Industry Canada:

AZ492FT4848 (P2081) AZ492FT4849 (P2082) Antenna Impedance:

Antenna Connector:

-40 dB 14 ms Typical 50 ohms mini-uhf RX Attack Time:

-57 dBm <1 GHz

-47 dBm > 1 GHz 60 ms Typical

*Typically 5 W in 8 ohms. Consult the product catalog sheets (ECAT Price Pages) for a list of disallowed frequencies. viii viii Glossary of Terms Countdown Delay State Disable Enable Inhibit Non-Priority Repeater PTT Priority Repeater Quick-Key Single Tone Burst The following glossary of terms and denitions help you to understand the VRS theory of operation. A term that describes the incremental step-down function of the counter in the repeater. Approximately 500 milliseconds of time delay for conventional modes and 1500 milliseconds for trunked modes separate each successive delay state. The specic condition of the counter. A series of eight delay states prioritize the repeaters within a common geographical area. Delay state zero has the least time delay (0 milliseconds); delay state seven has the greatest delay

(approximately 3.5 seconds for conventional modes, and 10.5 seconds for trunked modes). A unit that is in delay state zero is the priority unit. The deactivation of the repeater. Press the VRS button on the control head or switch the VIP input off. The activation of the repeater. Press the VRS button on the control head or switch the VIP input on. A condition that occurs when the countdown sequence of the logic circuitry of the repeater ends, or anytime the repeater stops transmitting. A repeater in any delay state other than delay state zero. This unit is inactive and does not repeat until the unit steps down to delay state zero. The Push-To-Talk button on a portable radio or mobile microphone. A repeater with its counter in delay state zero. This unit repeats any signal with the proper carrier frequency and PL code. A short press of the portables PTTone that is long enough for the VRS to key the mobile and access the trunking system, but less than 1 second in duration. When a repeater enables, it transmits a 700-millisecond audible tone. This tone burst increases the delay counter in all other repeaters within range of the transmitting vehicle by one delay increment. ix List of Abbreviations and Acronyms B-P CPS DPL HUB ICM ms PAC PL PPI P-B RF RX SB SBEP TOT TX VIP VRS VRS-EP VRS750 x Base to Portable Customer Programming Software Digital Private Line Hang Up Box In Car Monitor Millisecond Portable Area Coverage Private Line Portable Priority Interrupt Portable to Base Radio Frequency Receive Serial Bus Serial Bus Expanded Protocol Time Out Timer Transmit Vehicle Interface Port Vehicular Repeater System Vehicular Repeater SystemExpanded Protocol Vehicular Repeater SystemModel 750 x Introduction Description 1 The VRS750 Vehicular Repeater System is a mobile radio system component that provides on-site repeater capability between a portable radio and a base station (see Figure 1). The VRS gives the portable user the equivalent range of a mobile radio with the exibility of a portable. The VRS is not an ASTRO-capable radio; instead, it is designed to interface with an ASTRO Spectra mobile radio. It can only transmit and receive clear analog transmissions. The VRS receives transmissions on the portable radios transmit frequency with the proper access PL, and passes these portable signals to the mobile radio. The mobile radio re-transmits the signals to the base station on the mobile radios transmit frequency. NOTE: These transmissions have the mobiles ID, not the portables. Similarly, base station signals received by the mobile radio are sent to the VRS and re-transmitted to the portable radio. The VRS does not provide local repeater capability (received portable signals are not repeated on the portable receive frequency). The VRS-to-portable and portable-to-VRS communications are limited to clear analog only. This is a simplex-only interface; the VRS cannot receive and transmit simultaneously. The base station-to-mobile and mobile-to-base communications protocol is not limited to analog only. Rather, this interface is limited by the features and functions of the ASTRO Spectra and the base. SPEAKER CONTROL HEAD ASTRO MOBILE MOBILE MICROPHONE VRS750 HKN6153A Figure 1. VRS750 Vehicular Repeater System 1 Ordering Information The VRS is a crossband repeater that operates on either UHF or VHF frequencies. The repeater cannot be operated with a mobile radio operating in the same band as the VRS unit. The VRS RF platform is based on a synthesized transceiver. The VRS supports one channel whose frequency and channel spacing can be programmed in the eld. The VRS remains a simplex repeater and as a result, the transmit frequency must be set equal to the receive frequency. The VRS receives its programming information from the ASTRO Spectra mobile at power-up. The ASTRO Spectra mobile supports the VRS programming elds via ASTRO Customer Programming Software (CPS). For more information, refer to VRS750 Programming, in Chapter 2, Installation. The VRS is not compatible with ASTRO Spectra mobiles with the VSELP signaling type. When integrating a VRS with an ASTRO mobile with a Siren/PA, an alternate interface cable is needed (HKN6154A). This cable allows the VRS to be connected to the Siren/PA. For more information, refer to Installation, Chapter 2. When integrating a VRS with an ASTRO mobile with Dual Control heads, an alternate interface cable is needed (NKN6460A). This y-cable allows the VRS to be connected to the ASTRO mobile with two control heads. A separate antenna (not included) is necessary for use with the repeater. Typically, a one-quarter (1/4) wave length antenna maximizes radiation efciency when installed at the center of the vehicle roof. If it is necessary to mount the antenna on the vehicles trunk lid, an appropriate 3 dB gain antenna should be used. See VRS Antenna Installation, in Chapter 2, for details. A lter for the battery lines (TLN5277B)is available for use with ASTRO Spectra mobiles. This lter can be used to prevent excessive alternator whine noise from being heard on the mobile speaker during VRS operation. The VRS ships from the factory with the low output power setting at 275 mW and a high output power setting of 2 W. The low output power setting is the default setting. We recommend the LOW Transmit Power setting of 275 mW for optimal performance. This output power provides the VRS with a similar range as the portable when attached to a mobile antenna. Any deviation from this setting could result in a loss of communication from the portable to the base. The Global Tuning Tool (not included) can be used to tune the VRS output power in the eld. For more information refer to VRS750 Global Tuner, in Chapter 2. Contact Customer Resources for information on how to obtain this Global Tuning Tool. 2 VRS Features The VRS operates with the ASTRO mobile radio and contains the following integrated features:

Automatic, multiple-unit, priority-resolution algorithm. Portable priority interrupt (PPI) function. Conventional/trunked operation. Remote switch enable/disable capability for control charger interface. Remote activation of emergency alarm feature. In-car monitor operation. VRS mobile access tones. Mobile radio transmitter steering of up to eight modes via Private-

Line (PL) code transmission from the portable radio. TX PL generator. Base repeater operation for two-frequency, simplex, xed-repeater systems. Mobile audio repeat. Compatible with the VRS-EP. All VRS features can be programmed in the eld using ASTRO Spectra mobile CPS. For more information, refer to VRS750 Programming, in Chapter 2. IMPORTANT NOTE: All ASTRO Spectra VRS systems with the same VRS RF transmit/receive frequency need to be CPS programmed identically to ensure proper operation. Failure to do so could result in erratic system operation. The VRS does not have to be installed in the system for programmingonly the mobile radio is programmed. If the VRS is not connected after programming the mobile system, an error message ERR 12/10 will be displayed on the control head. The VRS IS NOT compatible with the following mobile radio features:

W3 Control Head is not supported with VRS Flush-mounted control heads VSELP signaling type DataVRS and data are not compatible on the same channel and cannot be used simultaneously. VRS should never be activated on a channel that has packet data enabled, and VRS mode steering channels should not have packet data enabled. Scan Over-the-Air Rekeying (OTAR) Rekey Request 3 Mutually-Exclusive Features Message (from the Control Head)Trunking or Conventional Status (from the Control Head)Trunking or Conventional Emergency CallTrunking or ConventionalEmergency Call and VRS are mutually exclusive. Even if the mobile is programmed for Alarm and Call, when the Alarm case is exited, the mobile will not transition into Emergency Call while the VRS is activated. Likewise, if the mobile is in Emergency Call, the VRS cannot be activated. NOTE: When an Emergency Alarm is received, the dispatcher may elevate that talkgroup to Emergency status. Reprogram RequestTrunking Repeater Access ControlConventional Mobile Single ToneConventional Seven-Tone ModatConventional Motorcycle Consolette (Digital Remote and Tone Remote) The following mobile radio features may be received but may not be initiated or responded to while VRS is enabled. Private ConversationTrunking Call AlertTrunking or Conventional Telephone InterconnectTrunking or Conventional Voice Selective CallConventional 4 Installation 2 When selecting the location for the VRS, make certain that there is sufcient clearance for routing the antenna cable to the rear of the unit. VRS Installation The VRS750 is installed using the HKN6153A interface cable. The molded DB-25 end connects to the ASTRO mobile front connector. The DB-25 end with the plastic housing connects to the VRS (see Figure 2). Control Head VRS750 ASTRO Mobile HKN6153A Figure 2. Installing the VRS to an ASTRO Mobile If an external Siren/PA is to be used, the G334AC option must be ordered which replaces the HKN6153A cable with a HKN6154A cable, or a separate HKN6154A cable must be ordered. To install, plug the T side of the HKN6154A cable to the Siren/PA. Replace the mounting screw on the HKN4363B cable with the double length screw. Plug this side into the T cable. Plug the DB-25 end of the HKN6154A into the VRS (see Figure 3). Control Head Siren/PA ASTRO Mobile HKN4363B VRS750 HKN6154A Figure 3. Installing the VRS750 with an External Siren/PA 5 Installation of the Mounting Trunnion, HLN6855 1. Select the location to mount your VRS750. The VRS750 must be mounted within six feet of the mobile radio. Allow sufcient space around the VRS750 for free air ow for cooling. 2. Using the trunnion mounting bracket as a template, mark the positions of the holes on the mounting surface. 3. Center-punch the spots you have marked and drill a 4 mm (0.16 inch) hole at each. 4. Secure the trunnion mounting bracket with the four screws provided (see Figure 4). 5. Connect the VRS-to-Mobile cable to the 25 pin connector on the bottom of the VRS750. 6. Position the VRS750 in the trunnion. 7. Secure the VRS750 with the two wing screws, and the split and at washers provided. Figure 4. Securing the Trunnion Mounting Bracket 6 VRS Antenna Installation Recommended mobile antenna installations are limited to metal body vehicles at the center of the roof and center of the trunk deck locations. 1. Mount the antenna using the instructions provided with the antenna kit by the manufacturer (an antenna is not included with the VRS models). Mount the antenna as far from the mobile radio antenna as possible, never less than three feet. An ideal conguration would be a roof-mounted mobile radio antenna and a trunk-

mounted VRS antenna. 2. Run the coaxial cable to the VRS750 mounting location. If necessary, cut off the excess cable and install the cable connector. 3. Connect the antenna cable mini-UHF connector to the antenna jack on the rear of the VRS750 (see Figure 5). A mini-UHF crimp connector is provided with each VRS750 unit for easier installation with a pre-existing antenna. Ensure that the antennas cable connector is fully tightened. An adapter should NOT be used between the antenna cable mini-UHF connector and the VRS750. VRS750 Programming ANTENNA CONNECTOR Figure 5. Connecting the Antenna Cable Mini-UHF Connector to the Antenna Jack The user selectable operating parameters for the VRS750 reside in the ASTRO mobile EEPROM during normal operation. The EEPROM located in the VRS750 holds the tuning parameters. The VRS750 programming windows reside in ASTRO Spectra CPS and are accessible when the VRS-EP Option is enabled in CPS under the Radio Conguration --> Radio Wide --> Advanced Window (see Figure 6). The VRS750 does not function without CPS programming and is not pre-programmed at the factory. To ensure operational compatibility from one unit to the next within the eet, all of the ASTRO Mobile and VRS750/VRS-EP systems should be programmed the same way. 7 Figure 6. Advanced Window

(Radio Conguration --> Radio Wide --> Advanced) Special Programming Notes The VRS button can be located in any of the indicator button positions normally used for option buttons. The VRS750 option can be enabled/disabled by a vehicle interface port

(VIP). Use the VIP Control of VRS box in the Radio Conguration

--> Radio Wide --> VRS window (see Figure 8) to enable VIP control and to select whether the input control is active open or active closed. Then use the Radio Conguration --> Radio Wide --> Radio VIP window (see Figure 7) to select the VIP to be used. However, the VRS button must still be added to the control unit if it is desired to have the indicator light when the VRS750 is enabled. See the ASTRO Spectra CPS users manual for details concerning programming the VIP. NOTE: The ASTRO Spectra CPS users manual does not indicate that the VRS button is required in order to have the indicator light when the VIP is enabled. 8 ASTRO VRS Programming Windows Figure 7. Radio VIP Window

(Radio Conguration --> Radio Wide --> Radio VIP) There are ve windows for editing the VRS Option. Four of these windows are in the Radio Wide section of Radio Conguration while the fth window is a table for the VRS mode steering PLs. The rst window is the VRS subsection of the Radio Wide options (see Figure 8). In this window Base Repeater, Mobile Detector, Flashing Display, VIP control of VRS, and Trunking Access Tones can be enabled or disabled by clicking in the box to the left of the option. This window is also where the ICM mode can be selected using a pull down menu. Enabling Base Repeater will add 300 ms of delay to the prioritization routine to account for xed repeater attack time. The second window is the VRS Private Line subsection (see Figure 9). This window allows the user to select a Mode Steering type, if one is being used. If Mode Steering is set to Disabled, the Access PL Freq. and Access PL Code elds will become user selectable. These elds specify the one PL frequency transmitted by the portable that will be used to access the VRS750. The VRS750 will treat that access PL in the same manner as a select mode mode steering PL. To edit these elds click in the Access PL Freq. or Access PL Code box and use the pull down menu to select the desired frequency or code. Also located on the second window is the VRS Tx Squelch Type. To edit this eld click in the box to the right and use the pull down menu to choose between TPL and CSQ. If TPL is selected, meaning that the VRS should transmit to the portable with PL, the VRS Tx PL Freq. and VRS Tx PL Code elds will become user selectable. To edit these elds, click in the VRS Tx PL Freq. or VRS Tx PL Code box and use the pull down menu to select the desired frequency or code. 9 Figure 8. VRS Window

(Radio Conguration --> Radio Wide --> VRS) Figure 9. VRS Private Line Window

(Radio Conguration --> Radio Wide --> VRS Private Line) 10 The third window is the VRS Advanced subsection (see Figure 10). This window is used to enable/disable the Access Acknowledgment and Time-Out-Timer Tones and Repeater Portable Priority Interrupt

(PPI) as well as selecting the Time-Out-Timer duration. The Time-Out-

Timer duration may be set to 30, 60, or 120 seconds, or innite. The innite setting should be used with caution, since damage to the transmitter could result from any extremely extended transmission. It should be noted that the Repeater PPI feature must be enabled to allow the multi-unit priority algorithm to function correctly when there will be multiple VRS units on scene. The time between interrupts may be set to Fast (500 ms) or Slow (2 seconds) for conventional modes and Fast (500 ms) or Slow (1 second) for trunked modes. NOTE: When using Rptr PPI, the receiver squelch setting of the portable must be programmed for CSQ (carrier squelch). Figure 10. VRS Advanced Window

(Radio Conguration --> Radio Wide --> VRS Advanced) The fourth window is the VRS Personality subsection (see Figure 11). The VRS Personality sets the VRS Frequency Band, Simplex Frequency, Channel Spacing, and TX Output Power for the VRS750. The VRS750 can be programmed for 12.5, 20, or 25 kHz Channel Spacing with a High or Low output power (factory power settings are 2 W for High and 275 mW for Low). Note that the VRS Personality will allow the Frequency Band to be set to VHF, UHF R1, or UHF R2 regardless of which model VRS750 is being used, but upon power up the error message VRS 001 will be displayed if the frequency band is incorrect. 11 NOTE: Older VRS units, such as the VRS-EP, do not support any of the elds in the VRS Personality window. However, these elds can be programmed without having any effect on the VRS-EP, so that the VRS-EP and VRS750 can be interchangeable without reprogramming the mobile. Figure 11. VRS Personality Window

(Radio Conguration --> Radio Wide --> VRS Personality) The VRS Personality can be programmed directly into the VRS750 EEPROM using Professional Radio CPS and a new dip switch conguration, Professional CPS Mode. All other operating parameters will still be programmed using the ASTRO Spectra CPS. For more information, refer to Mode Conguration, Chapter 6. The fth window, Radio Conguration --> Radio Wide VRS-EP Mode Steering --> VRS-EP Mode Steering List --> VRS-EP Mode Steering - 1 (see Figure 12) is a table containing PL and mode steering information that can be edited. Mode Steering must rst be enabled in the VRS Private Line window before the mode steering PLs in the table can be edited. To enter the PL codes used in mode steering and their corresponding destinations, enter the desired PL code or frequency by using the pull down menu in each PL Freq. or PL Code box. Then select the corresponding Steering Destination in the same manner. If the VRS Tx Squelch Type was set to TPL in the VRS Private Line window, none of the mode steering PLs may be the same as the VRS Tx PL Frequency. 12 NOTE: The Receive PL lter internal to the VRS is a low pass lter with a -3 dB point of approximately 170 Hz. As a result, the PLs greater than 170 Hz will be attenuated to allow for a decreased decode sensitivity. The higher the PL frequency the greater the attenuation. The Emergency, Message, and Status features of the VRS are best suited for use with these higher PL frequencies. Figure 12. VRS-EP Mode Steering Window Due to Host memory considerations, the maximum number of Zones allowed to be accessed by the VRS Mode Steering window is 20. Any Zone number greater than 20 will not be allowed in this window but is allowed for normal radio operation. The Tuner for Professional Radios (Global Tuner) can be used to adjust the VRS750s Transmitter Output Power and Receiver Squelch Settings while in Normal Mode (see Table 6 in Chapter 6). In order to program the VRS750 using the Global Tuner it should be connected to the mobile and to a PC via its COM port as indicated in Figure 13. VRS750 Global Tuner VRS750 SRIB VRS750 TO MOBILE CABLE CONNECT TO THE PCs COM PORT ASTRO MOBILE Figure 13. VRS Connection to the PC 13 Once the setup is complete and the mobile is turned on the current tuning parameters can be read from the VRS750 by selecting File -->

Read Radio Information and Softpots on the Global Tuner. NOTE: Radio Serial Number and Radio Model Number shown at the bottom of the screen will not match the model number and serial number of its associating VRS. The VRS750 supports 2 different power levels (High and Low). There are separate alignments for High and Low power (see Tables 2 and 3). We recommend setting and using a Low transmit power setting of 275 mW for optimal performance. This output power provides the VRS750 with a similar range as the portable when attached to a mobile antenna. Any deviation from this setting could result in a loss of communication from the portable to the base. NOTE: Please also note that some countries may have different restrictions on the power level. If you are not sure on the power to tune, please check with your regulatory body. The maximum available power level given in the table below must not be exceeded. NOTE: When checking the RF power output of the VRS750, always use an attenuator pad of at least 30 dB attached to the radio end of the RF cable. This will avoid an RF mismatch and ensure a stable RF reading that will not change with varying lengths of connecting cable. NOTE: The VRS750 will be programmed from the factory with a high power setting of ~2 W and a low power setting of ~275 mW. Table 2. Transmit High Power Level for VRS750s RF Band (MHz) High Power (W) VHF (136-174) UHF Band 1 (403-470) UHF Band 2 (450-527) 5.2-5.7 4.2-4.6 4.2-4.5 To perform Transmit High Power Tuning, do the following:

1. Under the Tx Align menu, select Transmit Power, then select High (see Figure 14). 2. Press PTT Toggle. This will key the radio up at F1. 3. Adjust the high power level by moving the slider/spin control or keying in values in the edit control (press ENTER to conrm selection after typing in the softpot value). 4. Press PTT Toggle to dekey the radio, go to the next frequency point by selecting the slider, typing in the edit control box (press ENTER to conrm selection after typing in the softpot value) or toggling the softpot value using the spin control. Transmit Power Tuning 14 Figure 14. Transmit High Power Window in the Global Tuner 5. Press PTT Toggle again to key up the radio at the selected frequency point. 6. Repeat steps 3-5 for (F2-F7). 7. Press Program to store the softpot values into the radios codeplug. 8. Exit the Transmit High Power function. The mobile will reset upon exiting If low power channels are used, perform Transmit Low Power Tuning as shown in Table 3. Table 3. Transmit Low Power Level for VRS750s RF Band (MHz) Low Power (mW) VHF (136-174) UHF Band 1 (403-470) UHF Band 2 (450-527) 240-310 240-310 240-310 To perform Transmit Low Power Tuning, do the following:

1. Under the Tx Align menu, select Transmit Power, then select Low. 2. Press PTT Toggle. This will key the radio up at F1. 3. Adjust the power level by moving the slider/spin control or keying in values in the edit control (press ENTER to conrm selection after typing in the softpot value). 15 4. Press PTT Toggle to dekey the radio, go to the next frequency point by selecting the slider, typing in the edit control box (press ENTER to conrm selection) or toggling the softpot value using the spin control. 5. Press PTT Toggle again to key up the radio at the selected frequency point. 6. Repeat steps 3-5 for (F2-F7). 7. Press Program to store the softpot values into the radios codeplug. 8. Exit the Transmit Low Power function. The mobile will reset upon exiting. Under Rx Align, select Squelch Attn. Select either Squelch Attn. 12.5 kHz, Squelch Attn. 20 kHz, or Squelch Attn. 25 kHz Channel Spacing variations (see Figure 15). Squelch Tuning Figure 15. Squelch Attenuation Window in the Global Tuner 1. Apply an RF signal modulated with 1 kHz tone at 60% rated deviation (see Table 10 in Chapter 7) for current frequency point

(F1 being the rst) of -110 dBm. Make sure that the mobile mic is off HUB and the VRS is programmed for ICM BOTH mode so that the audio will be routed to the mobile speaker. NOTE: The -110 dBm squelch level was chosen so that each VRS750 would have the same squelch performance as other VRS750 units as well as VRS-EP units. This prevents one unit from receiving a signal that the other cannot. 2. Set softpot to its maximum value to mute the radio. If the VRS750 remains totally unmute at this setting, leave it at the maximum setting and continue to step 4. 3. Adjust the softpot value by using the slider, keying in the edit box

(press ENTER to conrm selection), or using the spin controls. 16 Do this until the radio is totally unmuted. Verify the squelch closing by inputting a signal level of 4 dB lower (than that of the

-110 dBm level). 4. Repeat steps 1-3 for F2-F7. 5. Press Program to commit the softpot values into the codeplug. 6. Exit the Squelch Attn. function. The mobile will reset upon exiting. NOTE: The Auto Tuning feature does not work for the VRS750. Table 4 shows the softpot ranges to achieve approximately -110 dBm. The actual value varies from radio to radio. The VRS transceiver ships from the factory with the softpot set for -110 dBm. In the event that this value needs to be re-set in the eld, it is recommended that a communications analyzer or similar piece of test equipment be used to verify these settings. Table 4. Softpot Ranges Channel Spacing (kHz) Approximate Softpot Range for -110 dBm 25 12.5 25 12.5 25 12.5 56-63 63 44-52 63 43-46 63 Band VHF VHF UHF R1 UHF R1 UHF R2 UHF R2 Other adjustments can be made using the Global Tuner in the event that the transceiver is replaced. For more information, refer to Transceiver Board Tuning Procedure, Chapter 7. When all adjustments have been made, select File --> Program All. This will program all off the softpot values into the VRS750s EEPROM. The VRS750 rmware can be reprogrammed/reashed using the VRS750 Upgrade Kit. In order to use the VRS750 Upgrade Kit the VRS750 should be connected to a desktop or laptop PC via a COM port as indicated in Figure 13. The Flash adapter (NTN4056A) should be placed between the VRS750 programming cable (3085031D02) and the SRIB (see Figure 16). When connecting the VRS750 to the SRIB via the Flash adapter, make sure that the switch on the adapter is in the B position. With the ASTRO mobile powered on and PROG VRS displayed on the control head, the upgrade can be started. Open the VRS750 Upgrade Kit and click on the PROGRAM button. Follow the instructions through to the completion of the Flash process. Upon completion, place the switch on the Flash adapter back in the B position and disconnect the VRS750 from the programming cable. For more detailed information on the ashing process, consult the read me le for the Upgrade Kit. 17 VRS750 Upgrade Kit Figure 16. Flashing Adapter NOTE: The VRS750 Upgrade Kit will request which baud rate to use when ashing the rst radio. For the VRS750 the baud rate should not exceed 38,400 bps. Contact Customer Resources for information on how to obtain this VRS750 Upgrade Kit. 18 VRS Operation 3 General Control Unit The VRS is a crossband repeater that repeats either UHF or VHF portable transmissions though a VHF, UHF, or 800 MHz ASTRO mobile. The repeater cannot be operated with a mobile radio operating in the same band as the VRS unit. In multiple-VRS sites, the VRS uses a priority algorithm to prevent other VRS units from repeating. In this mode, only the highest priority VRS will serve multiple portable users. This prevents interference problems associated with multiple VRS units in proximity to one another. The VRS may be enabled/disabled from the ASTRO mobile radios remote-mounted W4, W5, W7, or W9 control head (see Figure 17). The VRS button may occupy any of the indicator button positions. Field programming determines the exact position. The VRS requires an ASTRO radio with a remote-mount control head. Astro XMIT BUSY Dir MPL VRS PA Siren Pri Non Pri 1 Wail 4 Mon 7 Mode Vol Sel Home

Rcl 0 Sql MODE ROCKER HOME BUTTON Figure 17. Typical ASTRO Control Head with VRS DIM 3 2 Yelp Hi-Lo 5 8 6 ExRad 9

Del When the VRS is turned on, the indicator illuminates and, after transmitting the Single Tone burst, the words VRS BOTH (indicating the In-Car Monitor mode) will be displayed momentarily. The indicator remains on for as long as the VRS is on. When the VRS unit is activated, it transmits Single Tone on the portable frequency, and assumes the priority (active) repeater state. The Single Tone frequency is xed at 847.5 Hz. For proper operation, all VRS units to be used in the same system must be programmed with 19 the same Single Tone frequency, as well as other VRS and ASTRO mobile features. Press the VRS button to disable the VRS option. When the system is turned off and then back on from the control head, the VRS option returns to the state it was in immediately before the control head was turned off. Another method of enabling/disabling the VRS option is through the use of a vehicle interface port (VIP). Using ASTRO CPS, the user can select which VIP to use and whether the input control voltage is to be high/ground or ground/high. One use of VIP operation connects the VRS switch lead to a portable radio vehicular control charger, such as the AVA, SVA, MVA, MTVA, or ASTRO XTS. Remove the portable from its charger pocket to automatically enable the VRS option. Replace the portable unit in its charger to disable the VRS option. A toggle switch on the portable unit charger allows the portable unit to be removed without enabling the VRS option. NOTE: This requires the VIP hardware interface kit, 0180757T61, which is not included with the VRS. Turning the portable unit charger off, then on does not disable the VRS option. The VIP setting controls the on/off state of the VRS option. If the eld programmer chooses the VIP option, pressing the VRS button on the control head will only cause the display to change momentarily to the In Car Monitor Mode (VRS BOTH). It will not enable or disable the VRS as previously described. It is still necessary, however, to select in CPS an indicator button for the VRS if it is desired to have the indicator light when the VRS is enabled. With the VRS on, press the portable radios PTT button to begin transmissions. The VRS programming must include correct PL frequencies to allow the portable unit to access the option. The VRS option receives signals with the correct PL, then uses the mobile radio to re-transmit the signals. The control heads XMIT indicator lights during the re-transmission. The VRS re-transmits received mobile signals as explained in the Mobile Audio Repeat paragraph on page 21. Note that the XMIT indicator does not light when the VRS is transmitting to the portable. To transmit directly to the other portable units, turn off the portable transmit PL. This allows you to talk around the VRS without transmitting on the mobile channels. The In-Car Monitor (ICM) feature is for use in a two-man operation where one user (user 1) is out of the vehicle while the other (user 2) remains in the vehicle. This allows user 2 limited access to both mobile and portable communications when the VRS is on, even when the repeater is the priority unit. ICM operation is set to BOTH. Vehicle Interface Ports VRS Access In-Car Monitor 20 ICM Transmissions VRS BASE:

Press the mobiles PTT to transmit on the frequency corresponding to the mode shown on the control heads display. If this mobiles VRS is the priority unit (in delay state zero), the VRS unit will then become non-priority upon the mobile PTT. If you press the mobiles PTT during portable-to-base VRS activity, a talk-prohibit tone sounds and the mic audio is disabled. VRS BOTH:

Press the mobiles PTT to transmit simultaneously on the frequency corresponding to the mode shown on the control heads display, and the portable frequency. Use the ASTRO CPS to enable the VRS TX PL generator option to transmit with the proper PL frequency. If you press the mobiles PTT during portable-to-base VRS activity, a momentary talk-prohibit tone sounds and the microphone audio is disabled. When using VRS BASE or VRS BOTH mode, all mobile transmissions are on the mode that is shown on the control heads display. If the VRS is currently steering to another mode, that steered mode will be displayed on the control head. Any mobile transmissions will be on that new mode until the portable steers the VRS back or the mode rocker switch is used to change modes. If the mode rocker switch is used to change modes, the portable user will not be made aware of this mode change. With Ack Tones are enabled, the portable user will hear a bad tone if the mode is changed during the transmission. The VRS option has no effect on mobile radio squelch control or normal mobile radio reception. The VRS portable units squelch setting is not user adjustable. Portable audio is heard from the mobile speaker of the priority VRS unit as shown in Table 5. Table 5. Portable Audio Heard from Mobile Speaker Mobile Microphone Portable Audio Heard from Mobile Speaker On HUB Off HUB PL*

CSQ

* = any valid repeater access PL Repeated portable transmissions will always be heard from the mobile speakers. Portable transmissions without proper PL will only be heard from the mobile speaker if the microphone is off HUB. The VRS transmits to the portable when audio unmutes the mobile speaker. This allows the user to set the monitor button on to defeat the coded squelch requirements of the mobile radio on a base-to-

portable transmission or off to prevent the VRS from repeating base-to-portable (HUB will also disable this), unless the coded squelch requirements of the mobile radio are met. Button presses (that is, Volume, Mode, etc.) on the priority mobile unit will also be transmitted by the VRS. 21 VRS Reception Mobile Audio Repeat Notes 22 Operation of VRS Options 4 Base Repeater Mobile Detector The following sections describe the operation of CPS eld-

programmable options of the VRS. This includes information about when to use an option and compatibility between options. For two-frequency simplex systems using a xed-site repeater, you can enable the base repeater option. This adds 300 ms of delay to the prioritization routine to account for the xed repeater attack time. This allows non-priority mobiles to detect any priority mobile in the system through the base repeater. The Mobile Detector feature allows the user to operate VRS units with two-frequency simplex dispatch systems without a base repeater. This feature allows the automatic multi-unit priority resolution algorithm to function in the above scenario. When this feature is activated by the CPS, a non-priority VRS will send a message to the mobile to enable a Listen Around feature when a proper portable PL is received. Listen Around switches the mobile radios receive frequency to match that of its transmit frequency of the steered mode. The non-

priority VRS will count down in priority if its corresponding mobile does not detect the repeated transmission on the Listen Around frequency. When the portable is dekeyed, the non-priority VRS will send a second message to the mobile to disable Listen Around and return to normal operation. This feature does not use any additional user modes in the mobile. NOTE:

The Mobile Detector feature only works on conventional modes. Trunked modes will be unaffected. VRS Transmit PL Generator The transmit PL generator, when enabled, causes the VRS to transmit

(base-to-portable), with specic eld programmable PL tones. The selected VRS transmit PL frequency cannot be the same as any of the VRS receive PL frequencies that the portable uses to access the vehicular repeater. VRS Mode Steering The VRS steering option gives the portable operator the ability to select the current mobile radio mode via PL tones. The total number of Mode-Steered modes can not exceed eight (including emergency, message, and status). The operator may program as many as eight such tones, along with corresponding mobile mode numbers, into the VRS. 23 The portable operator sets the channel or mode select switch to the position corresponding to the desired mobile mode and keys up the portable. The VRS unit decodes the PL tone and steers the mobile radio to the desired mode. There are two types of steering supported:

Transmitter Steering/Receiver Latching, and Transmitter Steering/

Receiver Steering. NOTE:

If mode steering is not selected during CPS programming, the programmer will need to enter the repeater access PL, which corresponds to a single access PL with select mode steering. Steering Types

<Transmitter Steering/Receiver Latching>On portable-to-base repeating, the mobile radio is steered to the proper mode as determined by the received PL from the portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio remains on this mode. Thus, all future base-to-portable repeating is heard via the mobile mode last steered by the portable. The mobile control head will display the steered/latched mode. If, sometime after this operation and while no repeat is occurring, the ICM user keys the mobile with the microphones PTT button, the mobile will now transmit on the latched mode that is displayed on the control head. If, however, the in-car-monitor

(ICM) user changes the selected mode using the mobiles mode rocker switch before pressing the mic PTT, the mobile will now transmit on the new selected mode. NOTE:

For the above type of steering, the portable user will be able to steer back to the selected user mode on the control head by programming one PL destination for Sel-Mode. However, the selected mode can be changed by the rocker mode switch.

<Transmitter Steering/Receiver Steering>On portable-to-base repeating, the mobile radio is steered to the proper mode as determined by the received PL from the portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio remains on this mode for 6 seconds. During this 6 seconds, the VRS waits for a repeatable base-to-portable transmission to be received. If a base-to-portable transmission is not received, the mobile will return to the last mode selected by the control heads rocker switch (current user-selected mode). If a base-to-portable transmission is received during the 6-

second timer, the timer will be reset back to 6 seconds and start over at the end of the transmission. If the portable is keyed during the 6 seconds, the VRS will handle the destination PL accordingly and reset the timer. If the 6-second timer has not expired, no repeat is occurring, and the ICM user keys the mobile with a microphone PTT, the mobile will transmit on the steered mode and the 6-second timer will start over at the end of the transmission. 24 Steering Destination Types There are ve types of actions, or steering destination types, that the VRS can be programmed to perform as a result of receiving a portable transmission with the specied PL:

Zone/Chan Select Mode Emergency Alarm Message NOTE: Each receive PL can only be used once and can only be programmed with one type of steering destination (for example, a single PL cannot be programmed to both change the mobile mode and send a message.) The VRS will command the ASTRO mobile to change to the mode programmed by the CPS. Once the mobile has steered, it will follow the conventions of the type of steering selected (for example, Transmitter Steering/Receiver Latching). The VRS will command the ASTRO mobile to return to the last mode selected by the rocker switch on the control head. If the portable user has steered to another mode, and the selected mode is changed in the car, the steering will be canceled until the VRS receives another mode steering PL. The VRS will initiate an Emergency Alarm through the ASTRO mobile, if the mobile is programmed for this type of Emergency, in the same manner as if the Emergency button on the control head were pressed. The type of Emergency (trunked or conventional) depends on the currently selected mobile mode, (trunked or conventional, respectively). The VRS will only generate an Emergency, not perform a portable-to-

base audio repeat, while the portable is transmitting on an Emergency request channel. This feature is typically implemented in the portable, using a one-touch button that has been programmed for Emergency-revert to a channel with the proper PL. Although the portable generates MDC tones, the VRS cannot decode MDC. Instead it responds to the PL of the portable mode on which the Emergency MDC tones are transmitted. All of this is transparent to the user. The VRS will command the ASTRO mobile to send out a CPS-

programmed message on the mode currently displayed on the control head, in the same manner as if the request to send a message had been generated using the control head. The VRS will send out only one message per received portable signal. No mode steering will occur; the currently steered/latched mode and the selected mobile mode will remain as they were before the request to send a message was received. If the message selected is valid, the VRS will transmit to the portable the mobile tones indicating whether or not the valid message was acknowledged. If the message selected is invalid, (either incorrectly programmed in CPS or not a valid message for the currently displayed mode), the VRS will send a low-pitched alarm tone to the portable. To generate a message request, the portable user would:

select the channel on the portable programmed for the message request, 25 Status momentarily press the PTT button, wait for the conrmation tone, and return the channel selector to a voice channel. The VRS will not perform a portable-to-base audio repeat while the portable is transmitting on a message request channel. NOTE: A message cannot be generated from the control head while the VRS is activated. The VRS will command the ASTRO mobile to send out a CPS-

programmed status on the mode currently displayed on the control head, in the same manner as if the request to send status had been generated using the control head. The VRS will send out only one status per received portable signal. No mode steering will occur; the currently steered/latched mode and the selected mobile mode will remain as they were before the request to send a status was received. If the status selected is valid, the VRS will transmit to the portable the mobile tones indicating whether or not the valid status was acknowledged. If the status selected is invalid, (either incorrectly programmed in CPS or not a valid status for the currently displayed mode), the VRS will send a low-pitched alarm tone to the portable. To generate a status request, the portable user would:

select the channel on the portable programmed for the status request, momentarily press the PTT button, wait for the conrmation tone, and return the channel selector to a voice channel. The VRS will not perform a portable-to-base audio repeat while the portable is transmitting on a status request channel. NOTE: A status cannot be generated from the control head while the VRS is activated. Time-Out Timer The Time-out Timer (TOT) duration value sets the maximum allowable time for a base-to-portable transmission. The VRS TOT may be set to 30, 60, 120 seconds, or disabled. When a unit times out, it counts up to delay state one. This removes it as the priority unit. VRS Single Tone When the VRS unit is enabled, it transmits an audible tone (Single Tone) for 700 mS which is used by other VRS units for the automatic prioritization routine. The Single Tone frequency is xed at 847.5 Hz. 26 VRS Mobile-TX Acknowledgment Tones

(Conventional Only) Flashing Display Repeater PPI When this option is enabled, the VRS transmits a 750 Hz feedback tone after it has received a repeatable message on the portable frequency. This signals the portable operator that the transmission was received. If the repeated message was cut short due to the mobile TOT being exceeded or the mobile channel being changed during the repeat, a lower-pitched tone (304 Hz) sounds. If the portable user does not hear a tone after completing a transmission, the portable is either out of range of the repeater or there is no priority repeater in the area. See VRS Mobile Trunking Tones (Trunking Only) on page 38 for a description of trunking acknowledgment tones. The Flashing Display feature causes the display on the control head to alternate between the current mode and VRS BOTH. This feature is used primarily when the VRS enable/disable button does not have an indicator light or when VIP activation is used. This feature is normally disabled in CPS. The length of time VRS BOTH is displayed every 6 seconds is determined by the temporary message display timer value. This value (from 250 to 6250 ms [default = 1000 ms]) can be programmed by the CPS. To congure, select Radio Conguration

--> Display & Menu --> Advanced screen. The Repeater Portable Priority Interrupt (PPI), when enabled, causes a base-to-portable transmission to be interrupted every 1 second in trunked mode or 2 seconds in conventional mode so that the repeater can search for a portable radio signal. (These times are programmable and may be changed to 500 ms for trunked or 500 ms for conventional modes). This interruption may be heard on the portable as a clicking noise, but PPI is necessary to give the portable user priority over base-

to-portable transmissions, for the self-clearing function of the automatic priority resolution feature, and to allow portable users in trunked mode to break in during system hang time to prevent loss of voice channel. This feature may be disabled through CPS. Quick-Key This feature allows the portable user to determine the status of the mobile trunking system. The feature is initiated by a short press of the portables PTT that is long enough for the VRS to key the mobile and access the trunking system, for less than 1 second in duration. 27 Notes 28 Detailed VRS Operation 5 Multi-VRS Operation Determining Priority Levels Portable-to-Base Transmissions The VRS is designed to accommodate multiple VRS units in the same area. This is accomplished by each VRS maintaining a priority level or delay state. During either portable-to-base or base-to-portable transmissions, only the highest priority VRS will transmit or cause a mobile PTT. The procedures for determining priority levels in multi-

VRS operation are discussed next. Whenever a VRS is enabled, it transmits a Single Tone burst (except if portable activity is already present). The Single Tone burst frequency is xed at 847.5 Hz. By default, when a VRS (VRS number 1) unit is enabled, it becomes the priority unit with a delay state of zero. When a second VRS unit (VRS number 2) is enabled in the area, it will transmit a Single Tone burst as described. Upon receiving this signal, VRS number 1 will know that another VRS is active and change its priority to delay state one from delay state zero. If a third VRS were to be enabled, VRS number 1 would change to delay state two and VRS number 2 would change to delay state one. This process could continue up until delay state seven is reached by VRS number 1, meaning that eight VRS units have been enabled. After eight VRS units are activated, they begin to stack up at delay state seven. If a portable begins to transmit, only the highest priority VRS will PTT its corresponding mobile for transmission to the base. The other VRS units, however, will be able to hear the portable transmission and monitor for mobile channel activity. Channel activity is veried by a squelch detect of the mobile. For non-priority units, the portables audio will be sent to the mobiles speaker (unmuted) from the VRS, not from the mobile. This allows the mobile to monitor the correct transmit frequency. If mode steering options are enabled then the non-priority VRS units monitor their mobiles channel activity on the channel steered to by the portables PL and not on the mobiles current user selected channel. The non-priority VRS units have a short delay in which they expect to see the squelch detect message. Conventional system units will wait at least 600 ms and trunking system units will wait at least 1500 ms. This time period is referred to as one delay state. If in the appropriate time frame a squelch detect message is not received, the priority VRS unit is assumed to have been disabled and all other VRS units will increase one priority level (for example, go from delay state 2 to delay state 1). The VRS units will continue to count down until a squelch detect message is received. In an extreme case, in which all but the lowest priority VRS units are disabled, it is possible that the remaining VRS unit which was the lowest priority (highest delay state) will have to wait up to 7 delay states before transmitting. This can lead to a transmission delay of up to 10.5 seconds for a trunking unit. 29 On conventional modes if the VRS <Base Repeater> option is enabled via CPS, then an additional 300 ms time delay is added to the delay states. This allows time for the mobile radios to transmit to and receive from a repeater site. When a base transmits, only the priority VRS unit will transmit to the portable. The other VRS units monitor activity on the portable channel. Similar to the previous case, if portable activity is not detected in the specied time frame after receiving mobile channel activity, the non-priority VRS units will decrease one delay state, until eventually one unit is in priority. During base-to-portable transmissions, the delay state timing is slightly different from that encountered during portable-to-base transmissions. On conventional modes, the rst delay state is 1 second; on trunking modes, the rst delay state is 3.4 seconds. All other delay states, on either trunking or conventional modes, are 400 mS. The worst-case delay for a unit to count into priority during a base-to-portable transmission in a trunking system would, therefore, be 5.8 seconds. See the description of the Portable Priority Interrupt feature on page 34 for information on the self-clearing feature used to re-

establish a single priority unit when multiple units are mistakenly in priority. This condition may occur when a VRS unit is activated before arriving on a scene, or in the unlikely case where several units stack up at delay state seven and all higher priority units (those in delay states one through six) leave the scene rst or are otherwise disabled. Normal radio communication between a VRS-equipped vehicle (unit A) and the base is via the mobile radio. When the operator decides to leave the vehicle and use the VRS option, simply press the VRS button or remove the portable from the charger if VIP operation is enabled to turn on the vehicles repeater. The repeater transmits the Single Tone burst on the associated portable radio frequency and sets the delay state to zero. When the delay state is zero, this unit is the priority unit. See Figure 18. IMPORTANT NOTE: The VRS is designed to be a stationary repeater system. The VRS unit should always be disabled when the vehicle is moving. FAILURE TO DO SO COULD RESULT IN ERRATIC SYSTEM OPERATION. Base-to-Portable Transmissions Single Unit Operation 30 Two-Unit Operation SINGLE TONE BURST UNIT A DELAY STATE ZERO PRIORITY UNIT MAEPF-26079-O Figure 18. Single VRS Unit Operation The arrival of another VRS-equipped vehicle (unit B) into the coverage area of unit A has no effect on unit As radio operation until unit Bs VRS is enabled. Unless there are portable transmissions occurring when unit B arrives, unit Bs repeater transmits a Single Tone burst when its VRS option is turned on. Unit Bs repeater priority counter initializes in delay state zero, making unit B the priority unit. Unit As repeater/portable receives unit Bs Single Tone transmission, which sets unit As repeater to delay state one. See Figure 19. Transmissions from portable units in the area now repeat through unit B. See Figure 20. SINGLE TONE BURST UNIT B DELAY STATE ZERO PRIORITY UNIT UNIT A DELAY STATE ONE MAEPF-26080-O Figure 19. Two-Unit VRS Operation A portable radios transmissions (solid arrows in Figure 20) go to all portable radios and VRSs in the area. Because unit B is the priority repeater, it repeats the portables signal (open arrows in Figure 20) to the base station and other mobile radios. Unit A cannot countdown and repeat until the delay state one time delay elapses. However, because unit A detects the mobile carrier of the priority unit (open arrow in Figure 20) before the delay expires, the priority counter does not begin the countdown. Unit A remains in delay state one and does not repeat portable transmissions. 31 TRANSMITS TO ALL REPEATERS AND PORTABLE RADIOS IN THE AREA TRANSMITS TO BASE STATION AND MOBILE RADIOS IN AREA UNIT B DELAY STATE ZERO PRIORITY UNIT UNIT A DELAY STATE ONE MAEPF-26081-O Figure 20. Two-Unit VRS Transmissions If unit B activates its VRS during portable transmissions, unit B does NOT transmit Single Tone or enable in delay state zero. Unit B must wait until it cannot detect the portable signal before transmitting Singletone and taking over as the priority unit as described above. Should another VRS-equipped vehicle (unit C) come into the area, the same sequence of events occurs as previously described in the Two-

Unit Operation section on page 31. Unit Cs arrival has no effect on unit As or Bs radio operation until unit Cs VRS is enabled. Unless there are portable transmissions occurring when unit C arrives, unit Cs repeater transmits a Single Tone burst when its VRS option is turned on. Unit Cs repeater priority counter initializes in delay state zero, making unit C the priority unit. Unit As repeater/portable receives unit Cs transmission which sets unit As repeater to delay state two. Unit Bs repeater/portable receives unit Cs transmission which sets unit Bs repeater to delay state one. Transmissions from portable units in the area now repeat through unit C. All lower-priority units will receive incoming portable transmissions, but will not key up their mobiles because they are in a delay state. See Figure 21. Three-Unit Operation 32 TRANSMITS TO ALL REPEATERS AND PORTABLE RADIOS IN THE AREA TRANSMITS TO BASE STATION AND MOBILE RADIOS IN AREA UNIT C DELAY STATE ZERO PRIORITY UNIT UNIT B DELAY STATE ONE UNIT A DELAY STATE TWO MAEPF-26082 -O Figure 21. Three VRS Unit Transmission Sequence The priority unit may change, depending upon the order in which they leave, as vehicles leave the coverage area. For example, in Figure 21, when unit A turns the VRS option off, it has no effect on the priority unit (unit C). Unit C continues to be the priority unit and repeat transmissions. When the priority unit (unit C) turns the VRS option off and conditions for repeater transmissions occur, the unit in delay state one

(unit B in Figure 21) counts down to delay state zero and becomes the priority unit. See Figure 22. IMPORTANT NOTE: Non-priority units (those in delay state 1 or higher) will not count down into priority if the portable user attempts to send a status or message. If there is no priority unit on scene, the request will be ignored. Departure of a VRS Unit 33

~ 2 sec

~ 6 msec VRS REPEATER TRANSMITTER PORTABLE TRANSMITTER WITHOUT PL PORTABLE TRANSMITTER WITH PL MOBILE TRANSMITTER ON OFF ON OFF ON OFF ON OFF MAEPF-26083-O Figure 22. Priority Unit Reassignment Rptr PPIPortable Priority Interrupt NOTE: When using Rptr PPI, the receiver squelch setting of the portable must be programmed for CSQ (carrier squelch).

<Rptr PPI> is CPS programmable. The main function of <Rptr PPI> is to allow the portable to interrupt base-to-portable transmissions. During VRS to portable transmissions, an interrupt is sent to the transmitter every 2 seconds on conventional modes and 1 second on trunking modes. (These times are CPS programmable and may be changed to 500 ms for trunked modes or 500 ms for conventional modes.) There is also a random time factor added to the base interval to prevent two VRS units from interrupting at the same time. This interrupt allows the receiver to monitor portable or other VRS activity for approximately 6 ms. See the timing chart in Figure 23. UNIT B DELAY UNITS 1 0 REPEATER WAITS ONE DELAY UNIT, COUNTS DOWN (1,0), AND BECOMES PRIORITY UNIT. THE PRIORITY STATE COUNTER IN OTHER REPEATERS ALSO COUNTS DOWN BY ONE DELAY UNIT. MAEPF-26084-O Figure 23. Portable Priority Interrupt 34 If a portables signal without PL tone is present when the repeater is interrupted, the repeater transmitter remains inhibited for the duration of the incoming signal. If the portables signal is modulated with a PL signal, the priority unit repeats the message back to the base station on top of the incoming signal. In addition to giving the portable user priority over all incoming signals, the Portable Priority Interrupt is used for three basic functions:

1. Self-ClearingThis is used when two or more priority VRS units are on the same scene. On the rst base-to-portable transmission, all priority VRS units will start to transmit. The rst one to have an interrupt and detect carrier without proper portable PL

(meaning another VRS is transmitting) will count up to priority state one, a condition which is referred to as self clearing. This will continue to happen until only one priority VRS is on scene. As an example, consider a case in which both units A and B are in the priority state (delay state zero). When conditions for repeater transmitting begin (i.e., the mobile receives a base signal), both VRS units begin transmitting. Figure 24 shows the unit B interrupt pulse occurring rst (due to the random time factor added to the interrupt interval). When unit B is interrupted, it detects another VRS unit transmitting and so unit Bs transmitter remains inhibited. Unit B is set to delay state one and unit A remains the priority unit since by the time unit As transmitter is interrupted, unit B is no longer transmitting. TWO UNITS IN PRIORITY STATE MOBILE RADIOS A & B RECEIVE MESSAGE REPEATER A TRANSMITS REPEATER B TRANSMITS INTERRUPT PULSE DELAY STATE 0 0 DELAY STATE 0 1 REPEATER A WAS NOT INTERRUPTED AND REMAINS THE PRIORITY UNIT. REPEATER B WAS INTERRUPTED BY ANOTHER REPEATER, THEREFORE DELAY IS INCREMENTED BY ONE UNIT. MAEPF-26085-O Figure 24. Self-Clearing Timing Diagram 2. Repeater HangtimeThis allows the user to get back into a conventional repeater or trunked system during hangtime. The timing is faster for trunked systems due to the added feature of talk permit tones being passed to the portable. If the portable keys up with proper PL, then the VRS will key up the mobile. If proper PL is not sent, the VRS will assume another VRS is in the area and count itself out of priority. 35 NOTE: If Repeater PPI is disabled on an analog trunking system with transmission trunking enabled, the Quick Key feature becomes useless, since the user will be unable to break-in during the repeater hangtime after the channel is acquired. For this reason, repeater PPI should always be ENABLED on an analog trunking system. 3. EmergencyThis allows the portable to have priority over dispatch. A drawback of portable priority interrupt is that during all base-

to-portable transmissions, the signal drops out for approximately 6-8 ms every: 2 seconds (conventional); or 1 second (trunking) if the slow PPI option is chosen; or every 500 ms (either trunking or conventional if the fast option is chosen in CPS). The repeater PPI function may be used by the portable user in the following manner:

During a base-to-portable transmission, the portable user wants to interrupt and transmit to the base. Portable must transmit with the VRS correct access or steering PL. When the VRS transmitter is interrupted, the VRS will detect channel activity from the portables transmission and switch to receive mode. The VRS will then transmit VRS TX Audio to the base. The VRS RX Audio is routed to the mobile speaker. As part of the multi-unit resolution prioritization algorithm, TX PL Self-Clearing operates by adding the VRS transmit PL to the list of PLs that the VRS monitors. If a VRS transmit PL is detected by a priority VRS (delay state 0), it will indicate that another VRS is transmitting. This feature will cause the original priority VRS to count up to delay state 1, 2, or 3, and allow the transmitting VRS to remain in priority. The delay state is randomized to prevent multiple units from stacking up in delay state 1. In order to prevent ICM transmissions from other VRS units affecting the priority states, the TX PL Self-Clearing feature only works when detecting TX PL from a VRS that is repeating a Base-

To-Portable transmission. This function is not programmable, but has no effect unless TX PL is used. This feature will not operate properly unless all VRS units are programmed to transmit with the same frequency PL, and the receiver squelch of the VRS750 units is set to approximately -110 dBm. NOTE: The VRS750 ships from the factory with a receiver squelch setting of approximately -110 dBm. If the VRS750 is not going to be programmed with a TX PL, then the Global Tuner can be used to loosen the receiver squelch for better radio performance. TX PL Self-Clearing 36 ICM Functions The in-car-monitor (ICM) allows limited use of the mobile while the VRS is enabled.

<ICM Base> Mode In this mode pressing the mobiles PTT will cause the mobile to transmit on the mode shown on the control head display. The VRS will not transmit the mic audio to the portable. During portable-to-base repeat operations pressing the mobiles PTT will result in the talk prohibit tone sounding momentarily and the mic audio will not be transmitted to the portable. When the mic is on HUB portable transmissions will not be heard at the mobiles speaker. When the mic is off HUB only portable transmissions with the proper PL will unmute the speaker. The following paragraphs detail how the VRS should operate in <ICM Base> mode during different cases. 1. No VRS repeat operations in progress and the mobile user initiates a PTT. The mobile will key up and transmit mic audio to the base. Mic-Hi line audio is not routed to the VRS transmitter. 2. During a portable-to-base repeat operation, the mobile user initiates a mic PTT. A momentary talk prohibit tone will be heard and the mic audio will be disabled. 3. During a base-to-portable repeat operation, the mobile user initiates a mic PTT. The base-to-portable repeat operation will be interrupted. Mic-Hi line audio is not routed to the VRS transmitter. The mobile will key up and transmit mic audio to the base. When the mobile mic PTT is released, the base-to-portable repeat will continue if the mobile is still receiving a base transmission.

<ICM Both> Mode In this mode pressing the mobiles PTT will cause the mobile to transmit on the mode shown on the control head display and cause the VRS to transmit to the portable. If the portable is using a PL frequency then the VRS can be programmed to transmit the proper PL. During portable-to-base repeat operations pressing the mobiles PTT will result in the talk prohibit tone sounding momentarily and the mic audio will not be transmitted to the portable. When the mic is off HUB all portable transmissions are heard at the mobiles speaker. When the mic is on HUB only portable transmissions with the proper PL will unmute the speaker. The following paragraphs detail how the VRS should operate in <ICM Both> mode during different cases. 1. No VRS repeat operations in progress and the mobile user initiates a PTT. Mic-Hi line audio is routed to the VRS and transmitted to the portable. 37 The mobile will key up and transmit mic audio to the base. 2. During a portable-to-base repeat operation, the mobile user initiates a mic PTT. A momentary talk prohibit tone will be heard and the mic audio will be disabled. 3. During a base-to-portable repeat operation, the mobile user initiates a mic PTT. The base-to-portable repeat will be interrupted. Mic-Hi line audio is routed to the VRS and transmitted to the portable. The mobile will key up and transmit mic audio to the base. When the mobile mic PTT is released, the base-to-portable repeat will continue if the mobile is still receiving a base transmission. NOTE: If the VRS is in a non-priority state all portable transmissions will be heard on the mobiles speaker. The above descriptions apply to a VRS unit in a priority state. When this option is enabled, the VRS transmits a feedback tone after it has received a repeatable message on the portable frequency. This signals the portable operator that the transmission was received. If the repeated message was cut short due to the mobile TOT being exceeded or the mobile channel being changed during the repeat, a lower-

pitched tone sounds. If the portable user does not hear a tone after completing a transmission, the portable is either out of range of the repeater or there is no priority repeater in the area. For trunked modes, the VRS regenerates the standard trunking access tones and transmits them to the portable. These tones, which are essentially the same as those heard at the mobiles speaker, are accessed with the quick-key feature. For this operation, the portable user briey (less than one second) presses the PTT button, and then listens for one of the following tones:

The talk permit tone (three short beeps) indicates to the portable user that the trunking system has granted a voice channel to the mobile and that keying the portable during the trunking system hangtime will result in acquiring this channel. The system busy tone (a telephone-like busy tone) indicates that, at the time the portable user dekeyed, the trunking system had no voice channel available. If the user does not key the portable again after receiving a system busy signal, a talk permit tone will be transmitted to the portable as soon as a voice channel is available. Acknowledgment Tones VRS Mobile-TX Acknowledgment Tones

(Conventional Only) VRS Mobile Trunking Tones (Trunking Only) 38 The talk prohibit tone (a long, low tone) indicates to the portable user that the mobile cannot access the trunking system. For portable transmissions lasting longer than one second (as opposed to a quick-key, which must be less than one second), the VRS will respond with one of the following tones. If the Trunking Access Tones option is disabled in the VRS Options screen of the ASTRO mobile CPS, the trunking access good tone and the trunking access bad tone will not be generated. The trunking access good tone (a single beep) indicates that a portable-to-base transmission has occurred and the mobile remained keyed for the entire transmission. The trunking access bad tone (a single, low-pitched tone) indicates that all or part of the portable-to-base transmission was not repeated or was interrupted during the portables valid PL transmission. This would handle, for example, the case of the mobiles TOT expiring or the case where a system busy is received rst, and then a talk permit, so that only part of the transmission could be repeated. This tone can also indicate that the VRS has counted down in priority from a delay state of 2 or higher. The talk prohibit tone (a long, low tone) indicates to the portable user that the mobile cannot access the trunking system. The system busy tone (a telephone-like busy tone) indicates that, at the time the portable user dekeyed, the trunking system had no voice channel available. If the user does not key the portable again after receiving a system busy signal, a talk permit tone will be transmitted to the portable as soon as a voice channel is available. Message/Status Acknowledgment Tones There are four different tones that the portable user can receive at the end of a message/status attempt:

Message/Status Acknowledged Good ToneThis tone is generated by the mobile when the message/status has been acknowledged by the base station. The VRS repeats the tone to the portable. Message/Status Not Acknowledged Bad ToneThis tone is generated by the mobile when the message/status has been transmitted but was not acknowledged by the base station. The VRS repeats the tone to the portable. Message/Status Not Supported Conventional Bad ToneThis tone is generated by the VRS when it receives a message from the mobile indicating that the message/status number selected is not a valid message or status while the mobile is on a conventional channel. Message/Status Not Supported Trunking Bad ToneThis tone is generated by the VRS when it receives a message from the mobile indicating that the message/status number selected is not a valid message or status while the mobile is on a trunking channel. 39 Non-Priority VRS Rules A priority VRS is placed into non-priority mode when one of the following occurs:

1. It receives a Single Tone burst at the xed frequency of 847.5 Hz. 2. During a base-to-portable repeat, it receives a VRS/portable frequency RF signal without proper PL during the PPI. When a VRS goes from priority to non-priority, the internal delay state changes from 0 to 1. Upon subsequent reception of Single Tone bursts

(that is, other VRS units activate in the same coverage area), the non-

priority unit will increase delay states up to a maximum of 7. While in non-priority, the following occur:

Portable-to-Base Non-Priority Operation 1. Upon reception of a portable frequency RF signal with proper PL, the VRS will determine if the mobile of another VRS system is repeating the signal. 2. For the prioritization routine to function, all of the mobiles with a VRS must be able to receive other mobile transmissions, either directly (TX=RX), or on a trunked system (TXRX), or through a base repeater (TXRX) in conventional modes with the <Base Repeater> feature enabled. For conventional non-repeater dispatch systems (TXRX), the Mobile Detector must be enabled for the prioritization routine to function properly. 3. The VRS will determine if the mobile of another VRS system is repeating the portable signal by steering the mobile to the mode corresponding to the received PL. If, within one delay state

(at least 600 ms for conventional, at least 900 ms for <Base Repeater>, and at least 1.5 seconds for trunking), the mobile in the non-priority VRS system does not receive the repeated signal, it will countdown from the current delay state. 4. Upon reaching delay state 0, the non-priority VRS will become the priority VRS and start repeating. The maximum delay for a non-priority VRS to countdown into priority is 4.2 seconds for conventional, 6.3 seconds for <Base Repeater>, and 10.5 seconds for trunking. 5. If the VRS does detect another VRS system repeating within the delay state, it will stop the countdown process and stay non-

priority. Base-to-Portable Non-Priority Operation 1. Upon reception of a repeatable base signal, the non-priority VRS will monitor for a VRS-to-portable transmission from another VRS system (that is, a signal on the portable frequency without proper VRS access PL). 2. If, within one delay state, the VRS does not receive the repeated signal, it will countdown from the current delay state. 40 Emergency Emergency Feature Summary 3. Upon reaching delay state 0, the non-priority VRS will become the priority VRS and start repeating. The maximum delay for a non-priority VRS to countdown into priority is 3.4 seconds for conventional and 5.8 seconds for trunking. 4. 5. If the VRS does detect another VRS system repeating within the delay state, it will stop the countdown process and stay non-

priority. If the VRS detects a portable frequency signal with proper PL while receiving a repeatable base signal, it will handle it according to the portable-to-base case. ICM Non-Priority Operation The ICM feature will continue to operate as described in the ICM Functions section except for the following:

1. While receiving a portable transmission with correct repeat qualiers, the unit will not repeat as long as the unit is non-

priority. 2. During a portable-to-base transmission with correct PL, the non-

priority VRS will steer the mobile to the mode programmed for that PL frequency. This allows the mobile to monitor for priority repeater trafc. An emergency alarm is initiated when the VRS receives a portable transmission which contains the Emergency Alarm PL, as programmed in the mode-steering screen of CPS. Upon decoding the Emergency Alarm PL, the VRS sends an enter emergency bus message to the mobile radio. The mobile radio will respond as if the Emer button had been pressed on the control head, and will proceed with the Emergency operation which is programmed by the CPS. In addition, an emergency acknowledgment tone is transmitted by the priority VRS as part of the automatic multi-unit priority resolution algorithm. The Emergency ACK tone generated by the VRS is a 1250 Hz tone lasting 500 ms in duration. Once in Emergency Alarm, the VRS ignores subsequent portable transmissions with the Emergency Alarm PL until the mobile exits Emergency. (The Emergency ACK tone, however, will always be generated in response to each portable transmission with the proper Emergency Alarm PL). Emergency Call and VRS are mutually exclusive. Even if the mobile is programmed for alarm and call, when the alarm case is exited, the mobile will not transition into Emergency Call while the VRS is activated. Likewise, if the mobile is in Emergency Call, the VRS cannot be activated. 41 Emergency Feature Operation Whether the mobile is programmed for silent or non-silent alarm is transparent to the VRS. However, the Emergency Alarm sequence changes slightly between the silent and non-silent case. The main differences are listed below:

1. The alarm exit sequence For non-silent alarm, any of the following will cause the mobile to exit Emergency:

Extended keypress of the Emer button on the mobiles control head. Mobile microphone PTT or a portable-to-base repeat. Mobile exhausts its retries without receiving an Emergency ACK from the base. The mobile receives an Emergency ACK from the base. For silent Alarm, any of the following will cause the mobile to exit Emergency:

Extended keypress of the Emer button on the mobiles control head. Mobile mic PTT or a portable-to-base repeat. 2. The mobile will not unmute due to base trafc during silent alarm, and therefore the priority VRS will not attempt a base-to-

portable repeat. If there are other, non priority VRS units in the area, they will perform the base-to-portable repeat without counting into priority. IMPORTANT NOTE: While in Emergency, attempts to send a message or status from the portable will be ignored and WILL NOT cause the mobile to exit Emergency. 42 Hardware Detailed Theory of Operation 6 Transceiver The VRS750 contains two main modules: a transceiver and an interface board. This module is an Analog synthesized FM device that contains the receiver, transmitter, and controller section. A ex cable connects the transceivers two accessory connectors to a single connector, J30, on the interface board. The RF jack is connected to W101 on the interface board via the 50 ohm coaxial cable. The VRS750 software is embedded in the digital portion of the transceivers controller which consists of a microcontroller and associated EEPROM, RAM, and ROM memories. NOTE: This transceiver cannot be used as a stand-alone portable. Interface Board This board provide power regulation, bus translation circuitry, audio routing circuitry, Single Tone Encoder and Decoder circuitry, programming circuitry, and mode conguration. Power Regulation Bus Translation Circuitry The VRS750 is powered by the mobiles Radio_SWB+ (13.8 VDC) at the connector P102-22. L101 and C137 are used to lter alternator whine from this signal before providing it as SWB+ to the interface board. The VRS750 utilizes the mobiles analog (P102-2, 10, 11, 21) and digital grounds (P102-18). U111 regulates the SWB+ down to +5 VDC. This voltage provides power for several switching transistors and voltage dividers on the VRS750 board. U118 i a micropower low dropout regulator used to provide +9.6 V for all of the analog audio circuitry. R162 and R164 form a divider network from this 9.6 V to produce the 4.8 V (VAG) used to bias the audio circuits. Finally, U129 is a three-terminal regulator used to provide the regulated 7.5V to the transceiver via Q113 in the reset circuit. SW7.5 V is provided to the transceiver at pad P31. The devices U100-2, U103, Q100, Q101, Q102, Q103, and Q104 are used to separate messages from the bi-directional SB9600 serial bus Bus+, Bus-, and Busy into and from the single direction RXD, TXD, BUSY OUT, and BUSY IN signals at the transceiver. The transceivers microcontroller can be reset by an external device by generating an active high reset pulse at pin P102-19, RADIO_RESET. This will cause Q109 to drive J30-5 low. 43 Audio Routing Circuitry Portable-to-Base Base to Portable In-Car-Monitor 44 There are four paths which are used to route audio between the mobile and the transceiver: AUX_RX_AUD, TX_AUDIO, MOB_MIC_HI and FIL_AUD. During the three types of communications of the VRS

(Portable-to-Base, Base-to-Portable, and In-Car-Monitor), the routing is as follows:

On channel RF signals are received by the transceiver through the connector, W101. The transceiver provides demodulated audio to the interface board at EXT_SPKR+ (J30-17) and URX_SND (J30-11). The receive audio at EXT_SPKR+ is volume controlled. The transceiver monitors the mobiles volume setting and then updates its volume accordingly. The audio is ltered by a 2-pole low pass lter, U107-1, which has a corner frequency of 3.2 kHz. T1, a 600-ohm to 600-ohm audio transformer, is used to isolate any ground noise such as alternator whine from the receive audio before being routed to the mobile at AUX_RX_AUD (P102-7). During portable-to-base transmissions the mobile routes this audio to its speaker. The receive audio at URX_SND is at a xed level of 260 mVrms. It is attenuated through op amp circuit U104-3 to a level of 60 mVrms which can be adjusted via potentiometer R146. T2, a 600-ohm to 600-ohm audio transformer, is used to isolate this audio from any ground noise such as alternator whine before being routed to the mobile at TX_AUDIO, P102-8. During portable-to-base transmissions, the mobile routes TX_AUDIO to its transmitter. The MIC_FIL_SEL (J30-15) and TONES-MOBILE_AUD (J30-8) control signals are generated by the microcontroller and are used to control audio routing circuits, U101-1 and U101-3, for Base to portable activities. FIL_AUD (P102-6)This audio path contains receive audio from the mobile during Base-to-portable transmissions. The receive audio passes through op amp circuit U104-1 and can be level adjusted via potentiometer R150. When a base-to-portable repeat occurs, TONES_MOBILE_AUD is in a low state and MIC_FIL_SEL is in a high state so that FIL_AUD is routed to the transmitter input (EXT_MIC, J30-19). The MIC_FIL_SEL (J30-15) and TONES-MOBILE_AUD (J30-8) control signals are generated by the microcontroller and are used to control audio routing circuits, U101-1 and U101-3, for In-Car-Monitor activities. MOBILE_MIC_HI (P102-12)This audio path contains microphone audio from the mobile during In-Car-Monitor (ICM) transmissions. The microphone audio passes through op amp circuit U104-4 and can be level adjusted via potentiometer R148. During an ICM transmission, both MIC_FIL_SEL line and TONES-MOBILE_AUD line are set to a Low state to congure both mux U101-3 and mux U101-1 to route the mobile mic audio to the transmitter input (EXT_MIC, J30-19). Single Tone Encoder Single Tone Decoder Boot Control Circuitry The VRS750 Single Tone Encoder (U100-1, U124-3, U124-2, and U124-

4) is used to produce a tone which is transmitted by the transceiver when the VRS750 is activated. Other VRS750 repeaters that are on in the operating area receive this Single Tone transmission. The other repeaters will then increment their priority counters by one while the transmitting VRS750 goes to delay state zero and becomes the priority repeater. When the VRS750 is in transmit mode for Single Tone, the microcontroller generates a square wave at a set frequency of 847.5Hz to the SNGL_TX_DATA (J30-6) pin. The control signal, TONES-

MOBILE_AUD, is set to a High state to allow the Single Tone signal to be routed to the input of the Single Tone Filter. The Single Tone Filter is a band pass lter that allows frequencies between 300Hz and 1.7 kHz. U124-4, R126 and R127 are for gain adjustment. The resulting sine wave is then sent to the transceiver to be transmitted on EXT_MIC

(J30-19). This circuit is also used when the transceiver generates various VRS750 acknowledgment tones. The VRS750 Single Tone Decoder (U100-1, U124-3, U124-2, and U124-1) detects other Single Tone transmissions, then increments the priority counter. VRS_TX*_RX from the microprocessor is set to a High state when the VRS750 is in the Single Tone Decode mode (receive mode). When this signal is high, U101-2 allows receive audio (URX_SND, J30-11) to pass to buffer U100-1. The output of the buffer drives the low-pass lter that is also used in the encoder circuit. U124-1 and the associated diodes, D100 and D101, produce a square wave which is divided down to 3.3V by R172 and R173. This signal, SNGL_DET(J30-12), is then sampled by the microprocessor to determine if Single Tone is present. The rmware for the VRS750 is stored in the transceivers Flash memory. This rmware can be programmed using the VRS750 Upgrade Tool (refer to VRS750 Upgrade Kit, Chapter 2). Prior to programming the rmware, the microprocessor must be placed into bootstrap mode. To place the microprocessor into bootstrap mode, it must be reset while the BOOT-CNTRL (J30-28) pin is grounded. This pin is grounded when the programming cable is connected and the ash adapter switch is turned to the A position. When the BOOT-CNTRL line is grounded, Q100 which controls U102 and U105, is opened and 9.6V passes through U102-2 to the base of Q112. Q113 opens and disconnects SW7.5 V from 7.5 V. At this point there is no supply voltage to the transceiver. Meanwhile, 9.6V is also applied to the base of Q112 thus charging up capacitor C182. After approximately 1.5 seconds, C182 is charged to a voltage that saturates Q111, causing Q112 to open and Q113 to turn 45 Program Sense On. SW7.5V is connected back to 7.5 V again. At this point the microprocessor on the transceiver has been reset and is now in bootstrap mode. To prevent mobile bus messages from corrupting the ash programming of the transceiver, the control signals to U102-3, U105-2 and U105-3 are applied with 9.6V to disconnect the Bus+ (P102-5), Bus- (P102-14) and Busy (P102-23)lines from the mobile when the BOOT-CNTRL line is grounded. The PROG_SENSE signal(J30-10) is monitored by the VRS to detect when the programming cable is connected at connector P101. This line will be pulled to ground when the programming cable is connected or will be 3.3VDC when the programming cable is not connected. The programming cable is used when adjusting the VRS using the Tuning Tool (refer to VRS750 Global Tuner, Chapter 2) or when updating the VRS rmware using the VRS750 Upgrade Kit (refer to VRS750 Upgrade Kit, Chapter 2). To prevent mobile bus messages from corrupting the codeplug programming and/or tuning of the transceiver, the control signal to U105-1 pin 10 is driven to ground. Mode Conguration There are various operating modes of the VRS750. The mode is selected at power-up based on the settings of dipswitch S1 pins 1, 2 and 3. Pin 4 is unused. Table 6 shows the supported modes:

Table 6. VRS750 Supported Modes Operating Mode S1 Pin 1 S1 Pin 2 S1 Pin 3 Normal Test Mode ATE Test Mode Professional CPS Mode On Off On Off On Off Off On On Off Off On Normal mode is the default and standard conguration for the VRS750. The Test Mode conguration is used when the transceiver requires tuning. The VRS750 can be put into Test Mode by placing S1 Pins 1, 2, and 3 to the OFF position before system power-up. When this setting is detected by the VRS P at power up, the following will occur:

VRS TEST is displayed momentarily on the control head. Portable Priority Interrupt is disabled. VRS TOT disabled. TX PL disabled. 46 To exit Test Mode, power down the VRS750 and recongure S1 for Normal mode. The ATE Test Mode conguration is used by Motorola for testing purposes. Professional CPS Mode is available for when the user requires the transmit and receive frequencies to differ. Operation during this mode is not advised and if required please contact your Motorola sales representative for details about this mode. All other combinations of the dipswitch are not supported and will default to the Normal mode. 47 Notes 48 Maintenance and Troubleshooting 7 Troubleshooting Procedures VRS Activation The following paragraphs contain information to help you maintain and troubleshoot the VRS. A list of recommended test equipment is found in the Recommended Test Equipment, Service Aids, and Tools section of the ASTRO Spectra Basic Service Manual, Motorola publication 68P81076C20. Additional information may be found in the Troubleshooting Chart in this manual. 1. Turn on the mobile radio control head. The radio should go through self-check and then display the home mode of the mobile radio. 2. Possible error messages on power up are:

ERR 12/10No VRS detected. See Common Power-Up Problems section on page 50 for possible solutions. ERR 12/81Flash EPROM failure. If re-ashing the unit does not x this problem the transceiver should be replaced. ERR 12/82Codeplug checksum error. After verifying that both mobile and VRS have the correct software version, checking the mobile-to-VRS connection, and moving the cable away from any interference, reprogram the VRS750s codeplug using the correct version of the CPS. If the codeplug cannot be corrected using CPS then the unit will need to have a new default codeplug written to the unit. Contact Customer Service for the default codeplug that corresponds to your model (see Table 7). Table 7. Default Codeplugs Band VHF UHF R1 UHF R2 VRS750 Model No. VRS750 Back Cover Kit No. Internal Codeplug No. P2080 P2081 P2082 PMLD4196 PMLE4242 PMLE4243 PMUD1479 PMUE1433 PMUE1476 49 ERR 12/84CONFIG register corruption. The unit should be ashed with the correct version software. If this fails to correct the problem, the transceiver should be replaced. ERR 12/88HC11 RAM failure. Replace the Transceiver. VRS 001VRS Synthesizer out of lock error. See Common Power-Up Problems section on page 50 for possible solutions. If the solutions in the Common Power-Up Problems section do not x the error then the transceiver should be replaced. PROG VRSThe VRS750 is in programming conguration. This is only an error if the programming cable is not plugged into the front connector of the VRS750. Reset the ASTRO Mobile radio and if the problem is not corrected check P101 Pin 9 and the PROG_SENSE line for any shorts to ground. 3. Enable the VRS unit by pressing the VRS button on the mobile control head. VRS BOTH must be displayed momentarily on the control head and the indicator must light. Verify a short single tone burst is transmitted upon activation at approximately 3 KHz deviation for a channel spacing of 25 kHz. NOTE: Because of the short burst, it may be necessary to verify the deviation on the modulation scope instead of the usual deviation meter. Activation may be repeated by pressing the VRS button once to disable the unit and again to reactivate it. 1. ERR 12/10 message is displayed on power-up. The VRS mobile interface cable is disconnected or bad. Verify the VRS Firmware is correct. Immediately after power up press the HOME button on the control head ve (5) times and verify the correct rmware version is displayed. Check all regulators for proper voltages. The 9.6-volt regulator is accessible at TP116. CAUTION: Do not probe U118 pin1 when the unit is powered. U118 will shut down without any recovery if pins 1 and 2 are accidentally shorted to each other. 2. VRS BOTH message does not display momentarily on control head when VRS is enabled. VRS is receiving a VRS frequency signal. (VRS will not display VRS BOTH or transmit Single Tone if there is RF activity on the VRS frequency.) Check the VRS750s squelch setting. 3. VRS 001 message is displayed on power-up. VRS Frequency Band in the VRS Personality of the ASTRO Mobile codeplug is incorrect. Common Power-Up Problems 50 Common Operational Problems Disassembly &

Reassembly Procedures Disassembly to Interface Board Level Remove Front Housing Check the VRS750s codeplug for incorrect programming. Re-ash the VRS750 with new rmware using the VRS750 Upgrade Kit. 1. Common Portable-to-Base Repeat Problems. Check portable for correct transmit frequency and PL. Check portable for low battery. Check VRS internal RF cable for loose connection. 2. Common Base-to-Portable Repeat Problems Check portable for correct receive frequency and PL. Check mobile for correct frequency. Check that portable is set for the bandwidth corresponding to the VRS. Check VRS internal RF cable for loose connection. The disassembly/reassembly procedure covers all VRS750 models. CAUTION: Refer to the Safe Handling of CMOS Integrated-Circuit Devices section at the beginning of this manual prior to disassembling the radio. 1. Disconnect the Programming Connector Cover by squeezing the top and bottom of the connector together, disengaging the bottom snap then the top and pulling straight out. 2. Remove the gasket within the recessed area for the 18-pin programming connector. 3. Insert a small at-blade screwdriver or like instrument in the side groove at the interface between the remote front housing and the main chassis (see Figure 25). Press while pulling the housing away from the chassis until the snap releases. Repeat the operation on the opposite side. 4. Pull front housing off the chassis. 5. Remove white retainer (p/n 4205395X01) from the header (or front housing). 6. Remove the 18 pin connector (2805347X01) from the front of the chassis. 7. Remove the front cover gasket. 51 Front Housing Main Chassis See Detail "A"

Detail "A"

Depress Snap Here Figure 25. Removing the Front Housing Remove the Top Cover 1. Insert a wide at-blade screwdriver or like instrument in the recess area on the side of the main chassis near the RF connector end (see Figure 26). 2. Pry the cover off the chassis by pushing the handle of the screwdriver in and toward the chassis. This will disengage the snap between the cover and chassis. 3. Repeat Step 1 and Step 2 for the opposite side of the radio. Detail A Disengage Snap here Disengage Snap here and on other side See Detail A Figure 26. Removing the Top Cover 1. Remove the antenna connector retaining clip by inserting a small at-blade screwdriver or like instrument between the clip and the top of the cavity wall as shown in Figure 27. Gently pry upwards. 2. Remove the board screws with a T-10 Torx Driver. 3. Carefully remove the interface board by rotating it out of the chassis. Slowly lift the board on the front edge while pushing up on the board through the accessory connector opening. Pull the board forward out of the chassis (see Figure 28). Remove the Interface Board 52 Front Pry Clip Off Here Figure 27. Removing the Antenna Connector Retaining Clip 4. Retain the heat conductive insulator from under the regulator. 2) Pull board forward out of chassis Transceiver Disassembly 1) Push up on board through accessory connector opening Figure 28. Removing the Interface Board 1. Detach the RF cable assembly from the right-angle SMB connector on the interface board. 2. Turn over the interface board. Remove the ex connector retainer, 4285168D01. 3. Gently lift the clasps of the 20-pin and 40-pin ex connectors. Remove the 20-pin and 40-pin ends of the ex cable from the transceiver leaving the 30-pin end attached to the interface board. 4. Loosen the screws for the two retainers holding the transceiver to the interface board. Slide one of the retainers away from the edge of the transceiver to free it. 5. Remove the transceiver from within the two retainers. 6. Detach the RF cable from the RF adapter plug. Unscrew the RF adapter plug from the transceiver. 53 VRS750 Reassembly NOTE: Replace all gaskets at each servicing to ensure proper sealing of unit. Transceiver Reassembly 1. Screw the RF adapter plug into the transceiver. Tighten until the stop on the adapter is fully seated in the RF jack. 2. Connect the RF coax cable to the RF adapter. 3. Place the transceiver in between the two retainers, sliding one sideways if needed. 4. Adjust the retainers so that they align with the groove between the transceiver board and its chassis. Tighten the four screws of the retainers. If needed, adjust the screws so that the transceiver lays at against the interface board. 5. Connect the 20-pin and 40-pin ends of the ex cable to the ex connector. Gently close the clasps on the connectors. 6. Reattach the ex connector retainer, 4285168D01. 7. Turn over the board. 8. Connect the RF coax cable to the right-angle SMB connector on the interface board. 1. Install a new gasket around the 25 pin connector and Antenna connector located on the board. 2. Check that the foam seal is correctly positioned on the 25 pin connector on the bottom side of the board. 3. Add the conductive insulator to the back of the regulator. 4. Insert the main board carefully at an appropriate angle

(approximately 30) into the chassis. Start, but do not torque down, screw number 6 per Figure 29 and Table 8. 5. Install the antenna retaining clip. 6. Attach the nylon washer to the regulator at screw hole number 4 as indicated in Figure 29. 7. Install the screws with 6-8 in-lbs of torque using a T-10 Torx driver per sequence shown in Figure 29 and Table 8. 8. Place a new cover gasket around the chassis ensuring that it is placed under the locking tabs and ledge at the front of the chassis

(see Figure 30). To ensure that the gasket remains seated along the groove, twist the gasket between ngers down and toward the chassis on both sides of the chassis. 9. If chassis is being replaced, add the plastic insert and seal into the area at the back of the main chassis opposite the antenna connector. 10. Install the top cover by engaging the hooks on front of the chassis and rotating the cover back. Ensure that the side snaps on the cover are engaged. 11. Install the front cover gasket over the front of the chassis ensuring that the rectangular hole in the chassis aligns with the rectangular hole in the gasket. Press the gasket ush against the chassis to ensure proper sealing. Interface Board Reassembly 54 4 5 1 2 6 3 7 8 Figure 29. VRS750 Torque Sequence Table 8. VRS750 Torque Sequence Step No. Screw P/N Bit Torque Notes 1 2 3 4 6 0310907A20 Torx T10 Start Only Place Antenna Conn. 4-8 1-3 0310907A20 Torx T10 8 in-lb Number 6 Inclusive 0310907A20 Torx T10 8 in-lb Twist o-ring Cover gasket Figure 30. Cover Gasket Location Assembly of Front Cover to Main Chassis Refer to exploded views on page 88 for parts referenced in this procedure. 1. Install the 18 pin connector into the female connector (mounted on the PC board) through the hole in the front of the chassis. 2. Place white remote retainer (4205395X01) over the 18 pin connector. 55 3. Install the remote front housing over the 18 position connector onto the front of the chassis ensuring that both snaps are engaged. 4. Place the gasket within the recessed area for the 18-pin programming connector. 5. Connect the Programming Connector Cover to the main chassis. VRS Transceiver Field repair of the transceiver is not recommended. Contact your local service representative for a replacement transceiver. If replacement of the transceiver is necessary, refer to the Disassembly & Reassembly section and the Tuning Procedure section. VRS Tuning and Alignment Setup ASTRO Spectra Station Cable Setup Tuning Procedure Interface Board Tuning Procedure 56 The VRS is tuned at the factory and should not need to be realigned. Refer to the proper manuals for programming and alignment for the associated portable radio and mobile unit before attempting to troubleshoot the VRS unit. If proper tuning of the associated radio fails to correct a problem, the following procedure may be used to align the VRS. Ensure that the ASTRO Spectra B+ cable is disconnected from the power supply and the control head is off (WARNING: Never turn B+

power off with the control head still on.) Connect the VRS DB-25 cable (HKN6153A) into the accessory connector of the mobile. Connect the other end of the VRS cable to the VRS. Set the test station power supply to 13.8 Vdc and current limiter to 12 amps. Connect the mobiles B+ cable to the power supply (see Figure 31). 1. Place the VRS in the test mode:

a. Turn off the mobile radio control head. b. Place the VRS into Test Mode by setting dipswitch S1 pins 1, 2, 3, and 4 to OFF. c. Turn on the mobile control head and re-enable the VRS. d. While in Test Mode, the VRS will not have portable priority interrupt and will not transmit PL with VRS-to-portable transmissions. e. Figure 32 illustrates the relative placement of the tuning potentiometers. 2. Adjust the VRS Deviation Level:

a. Set the Mobile Communications Analyzer RF output to

-50 dBm, with a standard test modulation (1 kHz tone, 3 kHz deviation). Mobile Communication Analyzer DC Supply

Speaker ASTRO Spectra Mobile VRS Communication Analyzer VRS750 HKN6153A Mobile Microphone W7 Control Head Figure 31. General Cabling Diagram 4 5 1 2 6 R148 R146 R150 3 7 8 Figure 32. Tuning Potentiometers 57 b. Set the Mobile Communications Analyzer frequency to the current mobile mode. c. Switch on the Mobile Communications Analyzer RF. d. Adjust R150 on the VRS board until 3.0 kHz deviation is obtained on the VRS Communications Analyzer. e. Switch off the Mobile Communications Analyzer RF. 3. Adjust the Mobile Microphone Deviation Level:

a. Inject a 1 kHz tone at 80 mVrms into the mobile microphone. b. Key the mobile microphone. (Refer to the ASTRO Spectra Mobile service manual for specialized equipment.) c. Adjust the signal level of the 1 kHz tone until 3.0 kHz deviation is obtained on the Mobile Communications Analyzer. d. Adjust R148 on the VRS board until 3.0 kHz deviation is obtained on the VRS Communications Analyzer. e. Dekey the mobile microphone. 4. Adjust the Mobile Deviation Level:

NOTE: Set the VRS Communications Analyzer RF output to

-50 dBm with a standard test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the VRS is programmed (750 Hz deviation). If the receive PL for select mode is not used, the Mobile Communications Analyzer frequency may need to be adjusted. a. Set the Mobile Communications Analyzer frequency to the current mobile mode. b. Switch on the VRS Communications Analyzer RF. c. Adjust R146 on the VRS board until 3.00 kHz deviation is obtained on the Mobile Communications Analyzer. d. Switch off the VRS Communications Analyzer RF. 5. Check the VRS RF Sensitivity:

a. Set the VRS Communications Analyzer RF output to -115 dBm with a standard test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the VRS is programmed (750 Hz deviation). NOTE: If the receive PL for select mode is not used, the Mobile Communications Analyzer frequency may need to be adjusted. b. Switch on the VRS Communications Analyzer RF. The unit should not retransmit this signal to the Mobile Communications Analyzer. c. Slowly increase the input signal. The unit should begin repeating to the Mobile Communications Analyzer at no more than -104 dBm. 58 Transceiver Board Tuning Procedure d. Switch off the VRS Communications Analyzer RF. 6. Take the VRS out of test mode:

a. Turn off mobile control head and set the dipswitch S1 pins 1, 2, 3, and 4 to ON. b. Turn on the mobile control head and re-enable the VRS. 7. Tuning is complete. The transceiver board can be tuned using the Global Tuner when the VRS750 is in ATE Test Mode. Connect the VRS750 to the test box

(RLN6394A) instead of the ASTRO Spectra mobile using the VRS750 ATE Cable (3080384N02) as shown in Figure 33. Before applying power, set dipswitch S1 pin 1 to ON and pins 2, 3, and 4 to OFF. This congures the VRS750 for ATE Test Mode. Make the appropriate connections to the VRS750 test box for power and audio. Once this is complete the VRS750 can be tested and tuned using the Global Tuner. VRS750 VRS750 PROG. CABLE SRIB VRS750 ATE CABLE

(3080384N02) VRS750 TEST BOX

(RLN5394A) RX AUDIO AND EXT MIC CONNECTORS CONNECT TO THE PCs COM PORT DC SUPPLY Figure 33. ATE Test Mode Conguration Front End Filter Tuning NOTE: Tuning is normally not required for VHF radios. It should only be performed if a radio has poor sensitivity. VHF radios are only tuned at one softpot frequency (F3: The values for the untuned frequencies are determined by adding the offset, calculated by subtracting the default softpot value for frequency F3 from the tuned softpot value for frequency F3. The default softpot values are listed in Table 9.) 59 Table 9. Default Softpot Values for VHF and UHF Frequency Point Softpot Value (Decimal) F1 F2 F3 F4 F5 F6 F7 VHF 36 57 84 124 166 195 225 UHF 38 48 79 110 135 161 186 Under Rx Align, select the Front End Filter option. 1. Inject a -70 dBm RF Signal with Frequency F1 (for UHF)/F3 (for VHF) modulated with 1 kHz tone at 60% rated deviation (see Table 10) into the VRS750. A 1 kHz tone must be detected at the RX Audio connector on the test box to verify that the radio is receiving. 2. Measure the RSSI voltage with a DC voltmeter capable of 1 mV resolution at test point 111 on the VRS750. It is recommended that an RCA lter (1.5 K-47 uF) be added at the input of the voltmeter to reduce RSSI noise. 3. Increment the softpot value by adjusting the slider, keying in the softpot values in the edit box (press ENTER to conrm selection) or using the spin control until the maximum RSSI voltage has been achieved. 4. For UHF and VHF radios:

a. UHF radios: Choose the next frequency and repeat steps 1 to 3 until all seven tuning points are done. b. VHF radios: Calculate the softpot offset by subtracting the default softpot value for F3 from the tuned softpot value for F3. Add the calculated offset to all default values and enter the results in the edit boxes for the appropriate softpot frequencies. 5. Press Program to commit the softpot values into the codeplug. 60 Table 10. VRS750 Deviation Levels Channel Spacing

(kHz) Rated System Deviation (kHz) Signal Generator Deviation (kHz) 12.5 20 20 25 30 2.5 4.0 5.0 5.0 5.0 1.5 2.4 3.0 3.0 3.0 Rated Volume Tuning Under Rx Align, select Rated Volume. NOTE: The received audio output is taken from the positive terminal of C189. 1. Inject a -47 dBm RF Signal modulated with 1 kHz tone at the 60%

rated deviation (see Table 10) into the VRS750. 2. Adjust the softpot value by using the slider, keying in the edit box

(press ENTER to conrm selection/send a softpot value), or via the spin controls. Repeat this until a 1.58 Vrms 200 mVrms signal can be obtained at the positive terminal of C189. 3. Press Program to commit the softpot value into the codeplug. Reference Oscillator Warp NOTE: Perform this operation prior to all other transmit tuning operations in order to minimize heating and because of the impact of warp on signaling operations. 1. Under Tx Align menu, select Reference Oscillator Warp. 2. There is only 1 frequency point shown which is always the last non 0 transmit frequency point, which will normally be F7. 3. Click on the slider thumb. Press PTT Toggle to key up the radio at the corresponding frequency point. 4. Monitor the transmit frequency. 5. Adjust the slider, spin or edit control (press ENTER to conrm selection/send a softpot value) until the frequency is as close as possible to the indicated transmit frequency (refer to Table 11). Table 11. Frequency Error Specications RF Band VHF (136-174) UHF Band 1 (403-470) UHF Band 2 (450-527) Target (Hz) 200 200 200 6. Dekey the radio by pressing PTT Toggle. 61 VCO Attenuation 7. Program the warp value into the radio by pressing the Program button. 8. Exit the Reference Oscillator Warp function. NOTE: The Transmit Deviation Limit softpot sets the maximum deviation of the carrier. Tuning is performed for 12.5 kHz, 20 kHz, and 25 kHz channel spacing. Tuning for 25 kHz channel must be done rst for all frequency points. Tuning for 12.5 kHz and 20 kHz channel spacing determines only the offset to the previously tuned deviation for 25 kHz tuning channel spacing. For (12.5, 20 kHz) channel spacing, only the last non 0 transmit frequency point (normally F7) will be used for tuning. VCO Attn. 25 kHz 1. Under the Tx Align menu, select VCO Attn. 25 kHz. 2. Begin with the lowest frequency. Select the thumb of the slider at the lowest frequency point and then press the PTT Toggle button to key up the radio at the corresponding frequency point. The spin control can also be toggled via its up/down arrow buttons. The softpot value can also be typed into the edit control (press ENTER to conrm selection/send a softpot value). 3. Inject a 1 kHz at 80 mVrms signal into the external mic connector on the test box (VRS750 input). 4. Note down the deviation obtained. 5. Adjust the slider, adjust the spin control or key in softpot values

(press ENTER to conrm) for the frequency point until the deviation is within range as dened in Table 12. 6. Dekey radio (press the PTT Toggle button). Choose the next frequency, key up and repeat steps 3 to 6 until all seven tuning points are done. 7. Program the softpot value by pressing the Program button. 8. Exit the VCO Attn. 25 kHz function. VCO Attn. 20 kHz NOTE: Tuning of Modulation Balance Attn. and VCO Attn. for 25 kHz channel spacing must be done rst. 1. Under the Tx Align menu, select VCO Attn. 20 kHz. 2. Press PTT Toggle to key up the radio at the last non 0 transmit frequency point (normally F7). 3. Inject a 1 kHz at 80 mVrms signal into the external mic connector on the test box (VRS750 input). 4. Note down the deviation obtained. 5. Adjust the slider, adjust the spin control or key in softpot values

(press ENTER to conrm) for the frequency point until the deviation is within range as dened in Table 12. 6. Press PTT Toggle to dekey the radio. 7. Program the softpot value by pressing the Program button. 62 8. Exit the VCO Attn. 20 kHz function. VCO Attn. 12.5 kHz NOTE: Tuning of VCO Attn. for 25 kHz channel spacing must be done rst. PA Bias Tuning UHF/VHF VRS750s (Procedure 1) 1. Under the Tx Align menu, select VCO Attn. 12.5 kHz. 2. Press PTT Toggle to key up the radio at the last non 0 transmit frequency point (normally F7). 3. Inject a 1 kHz at 80 mVrms signal into the external mic connector on the test box (VRS750 input). 4. Note down the deviation obtained. 5. Adjust the slider, adjust the spin control or key in softpot values

(press ENTER to conrm) for the frequency point until the deviation is within range as dened in Table 12. 6. Press PTT Toggle to dekey the radio. 7. Program the softpot value by pressing the Program button. 8. Exit the VCO Attn. 12.5 kHz function. Table 12. Deviation Specications for VRS750 UHF/VHF Radios Band Channel Spacing (kHz) Deviation (kHz) UHF/VHF UHF/VHF UHF/VHF 12.5 20 25 2.20-2.30 3.40-3.60 4.40-4.60 IMPORTANT NOTE: Tuning must be performed for both High and Low power for UHF and VHF radios. Take note that Procedure 1 IS NOT TO BE PERFORMED for UHF low power level tuning. Please refer to Procedure 2. 1. Ensure that the radios antenna output is terminated to a 50 Ohm load. This is to prevent self destruction of the PA. 2. Under Tx Align, select PA Bias, select High Power. 3. Measure/read the dc current drawn from radio (specications will vary from radio to radio). Call this X. This value should typically range from 70-100 mA or 0.07-0.1 A. 4. Press Toggle Voltage to enable the PA control voltage edit box/

spin control. 5. 6. Increase the Voltage softpot value and measure/read from current meter. Call the new value Y. Increase Y until Y-X is within the range given for PA current in Table 13. 7. Press Toggle Voltage again to disable the PA control voltage edit box/spin control. 63 8. Press Toggle Bias 1 in order to enable the PA Bias softpot. 9. Increase the softpot value to obtain Z until Z-Y is within the range for Bias Current as indicated in Table 13. 10. Press Toggle Bias 1 again to disable the PA Bias softpot. 11. Program the Bias softpot into the radios codeplug via pressing Program. 12. Exit the PA Bias High Power function. 13. Under Tx Align, select PA Bias, Low Power. (If UHF, skip to step 15 and continue to Procedure 2.) 14. Repeat steps 3-11. 15. Exit the PA Bias Low Power function. Table 13. PA Bias High Power Specications UHF/VHF VRS750s RF Band PA Current (mA) Bias Current (mA) VHF UHF Band 1 UHF Band 2 90-110 30-45 30-55 90-110 600-700 400-480 PA Bias Tuning for UHF Low Power VRS750s

(Procedure 2) NOTE: Failure in the instructions below means that you cannot get a reading which is within the range of the current window as specied in Table 14 for each individual step. Ensure that the radios antenna output is terminated to a 50 Ohm load. This is to prevent self destruction of the PA. STEP 1 1. Under Tx Align, select PA Bias, select Low Power. 2. Measure/read the dc current drawn from radio (specications will vary from radio to radio). Call this X. This value should typically range from 70-100 mA or 0.07-0.1 A. 3. Press Toggle Voltage to enable the PA control voltage edit box/

spin control. 4. 5. Increase the Voltage softpot value and measure/read from current meter. Call the new value Y. Increase Y until Y-X is within the range given for PA current in Table 14 (STEP 1) below.

****** If a failure occurs, go to STEP 2 otherwise proceed 6. Press Toggle Voltage again to disable the PA control voltage edit box/spin control. 7. Press Toggle Bias in order to enable the PA Bias softpot. 8. Increase the softpot value to obtain Z until Z-Y is within the range for Bias Current as indicated in Table 14 (STEP 1). 64 STEP 2

****** If a failure occurs, go to STEP 3 otherwise proceed 9. Press Toggle Bias again to disable the PA Bias softpot. 10. Program the Bias softpot into the radios codeplug via pressing Program. 11. Exit the PA Bias Low Power function. 1. Increase Y until Y-X is within the range given for PA current in Table 14 (STEP 2). 2. Press Toggle Voltage again to disable the PA control voltage edit box/spin control. 3. Press Toggle Bias in order to enable the PA Bias softpot. 4. Increase the softpot value to obtain Z until Z-Y is within the range for Bias Current as indicated in Table 14 (STEP 2).

****** If a failure occurs, go to STEP 3 otherwise proceed 5. Press Toggle Bias again to disable the PA Bias softpot. 6. Program the Bias softpot into the radios codeplug via pressing Program. 7. Exit the PA Bias Low Power function. STEP 3 1. Press Toggle Bias twice to reset the softpot value. 2. Press Toggle Bias again to disable the PA Bias softpot. 3. Measure/read the dc current drawn from radio (specications will vary from radio to radio). Call this X. This value should typically range from 70-100 mA or 0.07-0.1 A. 4. Press Toggle Voltage to enable the PA control voltage edit box/

spin control. 5. 6. Increase the Voltage softpot value and measure/read from current meter. Call the new value Y. Increase Y until Y-X is within the range given for PA current in Table 14 (STEP 3). 7. Press Toggle Voltage again to disable the PA control voltage edit box/spin control. 8. Press Toggle Bias in order to enable the PA Bias softpot. 9. Increase the softpot value to obtain Z until Z-Y is within the range for Bias Current as indicated in Table 14 (STEP 3). Table 14. PA Bias Low Power Specication for VRS750s (UHF Only) Step STEP 1 STEP 2 STEP 3 PA Current (mA) Bias Current (mA) 20-30 30-45 40-55 630-750 750-900 600-750 65 10. Press Toggle Bias again to disable the PA Bias softpot. 11. Program the Bias softpot into the radios codeplug via pressing Program. 12. Exit the PA Bias Low Power function. NOTE: After tuning a transceiver, go back and tune the interface board (details in this chapter) and then adjust the output power and squelch settings (see Chapter 2). 66 Troubleshooting Charts 8 Introduction to this Section This section contains detailed troubleshooting owcharts. These charts should be used as a guide in determining problem areas. They are not a substitute for knowledge of circuit operation and astute troubleshooting techniques. It is advisable to refer to the related circuit descriptions in the Hardware Detailed Theory of Operation, Chapter 6. List of Troubleshooting Charts Chart Number Description Page Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 VRS Enable Failure Error 12/10 Error 12/81 Error 12/82, Codeplug Checksum Error*

Error 12/84, Conguration Register Corruption*

Error 12/88, HC11 RAM Failure VRS 001, VRS Synthesizer Lock Failure Single Tone Encode Failure Single Tone Failure Base-to-Portable Repeat Failure Portable-to-Base Repeat Failure VRS ICM Audio Failure Serial Bus Failure Portable Audio at Local Speaker Issue Programming/Tuning Failure 68 69 69 69 69 69 70 71 72 73 74 75 76 77 78

*Older VRS-EP versions may show a 12/82 Error ashing every 5 seconds for Codeplug Checksum Error, and a 12/82 Error at power-up only for Conguration Register Corruption. 67 START Is VRS button enabled in the mobile codeplug?

Yes VRS ENABLE FAILURE No Is the mobile codeplug programmed for VRS VIP?

No Program mobile codeplug for VRS VIP. Yes Is the mobile codeplug programmed for VRS VIP active state?

Yes No Program mobile codeplug for proper VRS VIP active state. Is switch in correct VIP?

No Move switch or reprogram mobile codeplug. Yes Check VRS VIP switch input. Is mobile codeplug programmed for VRS VIP?

No Is

"VRS BOTH"

message displayed on button press?

No Reset system and start over. If CSQ is being detected the VRS will not enable. Yes Yes Program mobile codeplug for VRS button operation. VRS is now enabled. Chart 1VRS Enable Feature 68 ERROR 12/10 ERROR 12/84 START Is the VRS mobile interface cable connected?

No Reconnect the cable. Yes Are the regulated voltages present?

No Troubleshoot the regulator circuit. Yes Is the VRS750 firmware correct?

No Flash the VRS750 with the correct firmware. Yes Check the transceiver board. Chart 2Error 12/10 ERROR 12/81 ERROR 12/82 START START Reprogram the Flash Memory. Reprogram the VRS750 Codeplug. START Reflash the VRS750 with the correct version firmware. Reset the system. Is the 12/84 error still displayed?

Yes Replace the transceiver board. No Problem is corrected. Chart 5Error 12/84, Conguration Register Corruption ERROR 12/88 Error 12/88 Replace the transceiver. Chart 3Error 12/81 Chart4Error 12/82, Codeplug Checksum Error Chart 6Error 12/88, HC11 RAM Failure 69 VRS 001 FAILURE START Does the Freq. Band field in ASTRO CPS match the freq. Band of the VRS750 attached to the mobile?

No Correct the freq. band field for the VRS750 in the ASTRO mobile codeplug. Yes Replace the transceiver board. Chart 7VRS 001, VRS Synthesizer Lock Failure 70 SINGLE TONE ENCODE FAILURE No Replace the flex cable. START No Is 3.3VDC square wave at R114 during Single Tone burst?

Yes No No No No Is 80mVpp sinewave at TP104?

Yes Is the sinewave present at TP101?

Yes Is the sinewave present at the negative terminal of C104?

Yes Is there continuity between J30-19 and J20-7 on the flex cable?

Yes Replace the transceiver. Is there continuity between J30-6 and J40-21 on the flex cable?

Yes Replace the transceiver. Check and/or replace U100, U124. Verify that pin 10 of U101 is 0VDC during the Single Toneburst. Check U101 and Q106. Check and/or replace C104. Replace the flex cable. Chart 8Single Tone Encode Failure 71 SINGLE TONE FAILURE START Verify that the VRS750 dip switches are set to normal operation. Verify that J30-20

(boot control) is

~3.3VDC. Does TP105 pulse ~5VDC when the volume button is pressed?

Yes Does J30-21 pulse to ~0VDC when the volume button is pressed?

Yes Is there continuity between J30-21 and J20-9 on the flex cable?

Yes Check and/or replace the transceiver. No Check the mobile to VRS cable. No Check and/or replace U103 and Q103. No Replace the flex cable. Chart 9Single Tone Failure 72 BASE TO PORT. AUDIO ISSUES START Verify that the VRS750 dip switches are set to normal operation. Activate the VRS750. Provide an on-channel RF signal to the mobile. Yes Is "VRS BOTH" displayed briefly?

No The VRS750 is not enabled and audio will not be heard. Is audio present at C135?

No Chekc mobile and its connection to the VRS. Yes Yes Is audio present @ U101 pin No 5?

Check U104. Adjust R150 if necessary. Is audio present @ U101 pin 4?

Yes No Verify that the local mic is not pressed. Is pin 9 of U101 low

(0VDC)?

Yes Repair/replace U101. No Is there continuity between J30-15 and J40-23 on the flex cable?

Yes No Repair/replace Replace the flex Q114. cable. Is audio present @

TP101?

No Yes No Is pin 10 of U101 HIGH

-9.6VDC?

Yes No Is there continuity between J30-8 and J40-23 on the flex cable?

Yes Is audio present

@ J30-19?

No Replace the transceiver. Replace U101. Check and/or replace Q106. Replace the flex cable. Yes Is there continuity between J30-19 and J20-7 of the flex cable?

Yes Replace the transceiver. No Replace the flex cable. Chart 10Base-to-Portable Repeat Failure 73 PORTABLE-TO-BASE AUDIO ISSUE Verify dip switches are set to normal operation. Activate the VRS750. No Replace the flex cable. Is there continuity between J30-11 and J40-28 on the flex cable?

Yes Replace the transceiver. Is "VRS BOTH" displayed briefly?

No The VRS750 is not enabled and will not repeat. Yes Provide an on channel RF signal with an Access or Mode Steering PL to the VRS750. No No No No Is the 1kHz tone present @

J30-11?

Yes Is the 1kHz tone present at TP102?

Yes Is audio present @

TP125?

Yes Is audio present @

TP128?

Yes Replace transceiver. Check U104 and replace if necessary. Check solder connextions for C132, C133, and T2. Replace if necessary. Is mobile transmit deviation 3kHz?

No Adjust R146 to obtain 3kHz deviation from mobile. Yes Complete. Chart 11Portable-to-Base Repeat Failure 74 IN-CAR-MONITOR AUDIO ISSUES Verify that the VRS750 dip switches are set for normal operation. Activate the VRS750. Is "VRS BOTH" displayed briefly?

Yes PTT the mobile's local mic and talk into it. Yes During Base-to-Portable communications, is audio heard

@ the portable?

No Refer to the Base-to-Portable troubleshooting chart. Is audio present at C134?

No Check the mobile and its mic connections. Check C185 and C166 to make sure they have not been shorted to ground. Verify that the MOBILE_MIC_HI line in the mobile to VRS is ok. Yes Is audio present @ pin 3 of U101.?

No Check U104 and adjust R148 if necessary. Yes Is audio present @ pin 1 of U101?

Yes Is audio present @ pin 15 or U101?

Yes No No Is audio present @

J30-19?

No Yes Is pin 9 of U101 a logic HIGH -

9.6VDC.?

No Check and/or replace Q114. Yes Check and/or replace U101. Is pin 10 of U101 a logic HIGH -

9.6VDC.?

No Check and/or replace Q106. Yes Check and/or replace C104. Check and/or replace U101. Yes Replace the transceiver. Is there continuity between J30-19 and J20-7 of the flex cable?

No Replace the flex cable. Chart 12VRS ICM Audio Failure 75 SERIAL BUS FAILURE START Verify that the VRS750 dip switches are set to normal operation. Verify that J30-20

(boot control) is

~3.3VDC. Does TP105 pulse ~5VDC when the volume button is pressed?

Yes Does J30-21 pulse to ~0VDC when the volume button is pressed?

Yes Is there continuity between J30-21 and J20-9 on the flex cable?

Yes Check and/or replace the transceiver. No Check the mobile to VRS cable. No Check and/or replace U103 and Q103. No Replace the flex cable. Chart 13Serial Bus Failure 76 PORTABLE AUDIO AT LOCAL SPEAKER ISSUE START Verify that the VRS750 dip switch settings are set to normal operation. Activate the VRS750. Is "VRS BOTH" displayed briefly?

No The VRS750 is not enabled and audio will not be heard. Yes Provide an on-channel RF signal with the proper Access or Mode Steering PL to the VRS750. Is audio present @

EXT_SPKR+ J30-17?

No Yes No No Is audio present at C183?

Yes Is audio present at TP108?

Yes Adjust mobile volume on controlhead to level 7. No Replace the flex cable. Is there continuity between J30-17 and J20-4 on the flex cable?

Yes Replace the transceiver. Repair and/or replace U107. Check solder connections for C183, C103, and T1. Chart 14Portable Audio at Local Speaker Issue 77 PROGRAMMING AND TUNING ISSUES ATE Test Start Is the VRS750 in ATE Test or Normal Mode?

Normal Is 13.8V supplied to the test box?

No Supply 13.8V to the VRS750 test box. Is the mobile radio powered on?

No Power on the mobile radio. Yes Is the VRS750 programming cable securely plugged into the VRS750 and an SRIB?

Yes Is the SRIB connected to the computer and powered on?

Yes Is the Flashing Adapter being used?

Yes Yes No Plug the 25 pin connector into the SRIB and the 18 pin connector into the VRS750. Is

"PROG VRS"

displayed on the mobile control head?

No No Connect the SRIB to the serial port of the computer using a null modem cable and make sure it is turned on. No Verify that P101-7 is connected to J30-24. Yes Is the SRIB connected to the computer and powered on?

Yes Disconnect the programming cable from the VRS750. Verify that the mobile is powered on. If not, power the mobile on and start over. A. No Connect the SRIB to the serial port of the computer using a null modem cable and make sure it is turned on. Cycle power to the VRS750 and try again. If the problem persists, try a different programming cable. Did the mobile radio Yes reset?

No Plug the programming cable back in to the VRS750 and try again. Is the switch in the B position?

Yes No Place the switch in the B position and cycle power to the VRS750. The A position is for flashing only. Reset the mobile radio. Plug the programming cable back in to the VRS750. Remove the flashing adapter and cycle power to the VRS750. Try programming again. Yes Is "PROG VRS" displayed on the mobile control head?

No A. Chart 15Programming/Tuning Failure 78 PROGRAMMING AND TUNING ISSUES (CONT.) A. Is the Flashing Adapter being used?

No Yes Is there a 18 pin extension in the connector, 2805347X01, on the front of the VRS750?

No Replace the header block. Place the switch in the B position and reset the No mobile. Is the switch in the B position?

Yes Remove the Flashing Adapter and reset the mobile. The Flashing adapter could be bad. No Replace the programming cable. Yes Is the cathode of VR121 grounded when plugged into the SRIB?

Yes Verify that P101-7 is connected to J30-24. Chart 15Programming/Tuning Failure (Cont.) 79 Notes 80 Diagrams and Parts Lists 9 Introduction to this Section This section contains schematics, a component layout diagram, an exploded view, and electrical and exploded view parts lists. List of Diagrams and Parts Lists Description Printed Circuit Board Electrical Parts List Printed Circuit Board Component Location Diagram Printed Circuit Board Schematic Diagram Exploded View and Exploded View Parts List VRS-to-Mobile Cable VRS-to-Siren Cable VRS750 Programming Cable VRS750 Programming Cable Schematic Diagram VRS750 Flashing Adapter Schematic Diagram Page Number 83 84-85 86-87 88 89 89 90 90 90 81 Notes 82 VRS750 Vehicular Repeater System Printed Circuit Board Electrical Parts List

(PLN7780A) ITEM MOTOROLA PART NUMBER DESCRIPTION C100 C101 C102 C103, 104 C105 C107 C108 C109 C111, 112 C113 C114 thru 116 C117 C118 C119 C120 C121 C122 thru 131 C132, 133 C134, 135 C136 C137 C138, 139 C140 C141 C142 C143 C145 C146, 147 C148 C149 C150 C151 C152 C153 C154 C155 C156 C157 thru 161 C162 C164 thru 167 C168 C170 C171 C172, 173 C175 C179 C180 C182 C183 C184 C185 C188 C189 C190 C191 C194 C195 C196 C197 C198 C199 C200 C201 thru 208 D100, 101 D102 unless CAPACITOR, Fixed; pF:

otherwise stated 220 33 220 Polar, 1 F 0.1 F 220 0.1 F 220 220 2200

.01 F

.015 F 1000 0.22 F 0.1 F 100 220 Polar, 1 F 0.1 F 220 Polar, 2200 F 220 0.1 F

.01 F 220 0.1 F 1000 220 Polar, 1 F Polar, 10 F 220 Polar, 10 F 220 Polar, 10 F 220 Polar, 10 F Polar, 100 F 220 Polar, 100 F 220 0.1 F 220 0.1 F 220 220 220 1000 Polar, 10 F Polar, 1 F 220 0.047 F 220 Polar, 1 F 680 220 1000 220 0.1 F 220 0.1 F 220 0.1 F 220 2113740F59 2113740F39 2113740F59 2311049A08 2113741B69 2113740F59 2113741B69 2113740F59 2113740F59 2113741F33 2113741A45 2113741A49 2113740A79 2113743B21 2113741B69 2113740B49 2113740F59 2311049A08 2113743E20 2113740F59 2380090M40 2113740F59 2113743E20 2113741A45 2113740F59 2113741B69 2113740A79 2113740F59 2311049A08 2311049A19 2113740F59 2311049A19 2113740F59 2311049A19 2113740F59 2311049A19 2380090M25 2113740F59 2380090M25 2113740F59 2113743E20 2113740F59 2113743E20 2113740F59 2113740F59 2113740F59 2113740A79 2311049A19 2311049A08 2113740F59 2113743A13 2113740F59 2311049A08 2113741F21 2113740F59 2113740A79 2113740F59 2113743E20 2113740F59 2113743E20 2113740F59 2113743E20 2113740F59 DIODE:

4813825A08 MBD701 4813832C77 See Note 1 Transient supressor, 24 V ITEM MOTOROLA PART NUMBER DESCRIPTION ITEM MOTOROLA PART NUMBER DESCRIPTION F100 J30 L101 P101 P102 6580542Z01 FUSE:

3 A JACK:

0985173D01 Connector, 30 pin ex 2505462S03 COIL, RF:

Inductor, 1000 H PLUG:

0905904V02 Connector, J 2805429W03 Connector, P Q100, 101 Q102 Q103 Q104 Q106 Q109 thru 112 Q113 Q114, 115 4880141L02 4813824A17 4880141L02 4813824A17 4880141L02 4880141L02 4813821A21 4880141L02 See Note 1 TRANSISTOR:

NPN PNP NPN PNP NPN NPN nchan_tmosfet_gsd NPN R101 R102 R104, 105 R106 R107 R108 R109 R110 R111 R112, 113 R114 R115 R116 R117, 118 R119 R120, 121 R122, 123 R124 R125 R126 R127 R128 R129 R130 R131 R132, 133 R136, 137 R138 R139 R140, 141 R142 R143 R145 R146 R147 R148 R149 R150 R151 R155 R156 R157 R158 R159 R160 R161 R162 thru 164 RESISTOR: Ohms 5%; 1/8 W unless otherwise stated 68 k 10 k 100 4.7 k 6.8 k 68 k 100 k 15 k 27 k 100 k 330 k 75 k 30 k 4.7 k 6.8 k 10 k 27 k 10 k 56 k 15 k 10 k 100 k, 1%

27.4 k, 1%

22.1 k, 1%

100 k, 1%

4.7 k 10 k 4.7 k 1 k 4.7 k 1 k 4.7 k 47 k Pot, 20 k 4.7 k Pot, 20 k 56 k Pot, 20 k 100 k 10 k 1 k 15 k 360 1.8 k 15 k 820 10 k 0662057A93 0662057A73 0662057A25 0662057A65 0662057A69 0662057A93 0662057A97 0662057A77 0662057A83 0662057A97 0662057B10 0662057A94 0662057A84 0662057A65 0662057A69 0662057A73 0662057A83 0662057A73 0662057A91 0662057A77 0662057A73 0662057P95 0662057P27 0662057P22 0662057P95 0662057A65 0662057A73 0662057A65 0662057A49 0662057A65 0662057A49 0662057A65 0662057A89 1813905A11 0662057A65 1813905A11 0662057A91 1813905A11 0662057A97 0662057A73 0662057A49 0662057A77 0662057A38 0662057A55 0662057A77 0662057A47 0662057A73 R165 R166 R171 R172, 173 R174 R175 R180, 181 R182 R183 R184 R200 R210 R211, 212 R213'

R215 R216 R217 R220 R221 R224 R225 R226, 227 R228, 229 0662057A56 0662057A65 0662057T64 0662057A73 0662057P27 0662057A73 0662057A65 0662057A49 0662057A73 0662057A65 0662057A65 0662057A49 0662057A73 0662057A65 0662057A83 0662057B26 0662057A49 0662057B47 0662057A81 0662057A97 0662057A73 0662057A65 0662057A73 2 k 4.7 k 47.5 k 1%

10 k 27.4 k, 1%

10 k 4.7 k 1 k 10 k 4.7 k 4.7 k 1 k 10 k 4.7 k 27 k 1.5 M 1 k 0 22 k 100 k 10 k 4.7 k 10 k SWITCH:

S1 4080564C02 Dip T1, T2 2584422T02 TRANSFORMER:

6-pin U100 U101, 102 U103 U104 U105 U107 U111 U118 U124 U129 INTEGRATED CIRCUIT MODULE:

See Note 1 5113818A03 MC33072-1 5184704M60 MC14053B 5113806A37 MC14106 5113819A04 MC3303 5184704M60 MC14053B 5113818A03 MC33072-1 5113816A03 MC78L05A 5105109Z13 LT1129 5113819A04 MC3303 LM317T 5105469E18 VR102 thru 109 VR110 VR112, 113 VR115 VR118 VR121 VR123 4805129M35 4813830A28 4805129M35 4813830A28 4805129M35 4805129M35 4805129M35 See Note 1 DIODE:

Zener, 13, 5.6 V Zener, 13, 15 V Zener, 13, 5.6 V Zener, 13, 15 V Zener, 13, 5.6 V Zener, 13, 5.6 V Zener, 13, 5.6 V W101 W102 0984345R02 0905901V10 CONNECTOR:

SMB Jack Rt. Ang PCB J, Antenna Connector 8485176D01 0200835638 0300114832 MISCELLANEOUS:

Board, PC Nut Screw Notes:

1. For optimum performance, order replacement diodes, transistors, and circuit modules by Motorola part number only. 2. When ordering crystals, specify carrier frequency, crystal frequency, 3. crystal type number, and Motorola part number. Part value notations:

p=10 n=10

-6

=10

-3 m=10 3 k=10 6 M=10

-12

-9 VRS750 Vehicular Repeater System Printed Circuit Board Electrical Parts List (PLN7780A) 83 R150 1 5 1 R 0 6 1 C C172 C171 8 1 1 R V C179 1 3 1 R 0 3 1 R R132 R175 4 6 1 C 5 7 1 C 5 6 1 C 9 0 1 C VR112 VR115 VR113 1 S VR121 E 3 7 1 B C C 9 0 1 Q 5 6 1 R R133 TP104 R110 C107 16 R111 R112 4 8 1 R U101 8 9 R157 C206 E 5 2 1 B C C 6 0 1 Q 6 6 1 R 6 5 1 R E 4 8 1 B C C 4 1 1 Q 3 8 1 R R182 14 8 5 1 C 9 4 1 R U104 7 8 C124 5 4 1 R R148 R146 7 2 1 C 0 3 1 C 7 4 1 R 9 2 1 C 1 6 1 C TP106 6 2 1 C C135 6 3 1 C TP108 8 2 1 C TP109 1 3 1 C 4 3 1 C 6 6 1 C VR102 VR103 VR109 VR105 VR108 5 8 1 C R174 8 R129 2 1 R 1 7 1 R 6 2 2 R 0R181 8 1 R 16 0 0 2 C 9 9 1 C U105 8 9 E 8 0 2 B C 8 2 2 R C 5 1 1 Q 7 2 2 R 9 2 2 R TP119 TP116 C152 5 5 1 C 4 6 1 R C153 2 6 1 R R161 1 4 5 1 C 3 6 1 R 0 6 1 R 8 1 1 U 1 5 1 C 5 D102 0 5 1 C 9 5 1 R C148 TP117 7 4 1 C 8 5 1 R 9 4 1 C 9 2 1 U TP121 TP122 TP107 TP128 TP123 F100 TP124 TP127 TP125 TP126 VR104 7 0 2 C VR123 VR107 TP105 VR106 1 0 2 C 8 1 1 P T 1 0 1 D 0 0 1 D 9 1 1 C 0 7 1 C 1 4 1 C 5 2 1 R C180 R172 3 7 1 R TP103 14 7 2 1 R 6 2 1 R C118 R123 U124 7 8 R124 C117 R122 8 9 3 1 C 0 4 1 C 1 2 1 C 4 1 1 C 0 2 1 R 9 1 1 R 0 2 1 C 6 1 1 C R121 C115 R155 3 4 1 C 14 2 4 1 C 8 3 1 R C Q103 B E 6 3 1 R R137 C122 8 7 6 1 C 8 6 1 C 0 9 1 C 8 8 1 C 5 2 2 R C191 R224 C189 0 1 1 R V C138 8 9 1 C 7 9 1 C U102 8 9 2 8 1 C 5 0 2 C 16 R216 BE Q111 C R217 B E 2 1 1 Q C R213 R215 0 0 2 R C Q110 B E C202 R210 R211 C203 C204 2 1 2 R 3 1 1 Q 0 3 J TP113 TP111 0 3 1 0 1 R E 0 0 1 B C C 0 0 1 Q 2 0 1 R TP101 TP110 C104 TP102 5 0 1 C TP114 9 0 1 R TP112 8 0 1 R 1 1 1 C 4 1 1 R 5 1 1 R 0 4 1 R 9 3 1 R 6 4 1 C B E 4 0 1 Q C TP120 C145 2 0 1 C C108 6 1 1 R 3 1 1 R 2 1 1 C 3 4 1 R E 3 2 1 B C C 2 0 1 Q 2 4 1 1R 4 1 R R107 5 0 1 R 0 2 2 R R106 B E 1 0 1 Q C 4 0 1 R 1 0 1 C 1 2 2 R 3 1 1 C 4 9 1 C U100 4 5 7 1 1 R 8 1 1 R U103 7 8 U107 4 5 84 VRS750 Vehicular Repeater System Printed Circuit Board Component Location Diagram (Sheet 1 of 2) C137 C183 C103 1 6 1 T 3 4 C133 C132 1 6 2 T 3 4 L101 6 5 1 C C157 4 5 1 1 1 U 8 C159 C162 C195 C196 4 1 2 0 1 P 5 2 3 1 P31 P32 P33 W102 1 0 1 W 8 1 1 0 1 P 9 0 1 A V E R 1 0 D 6 7 1 5 8 4 8 VRS750 Vehicular Repeater System Printed Circuit Board Component Location Diagram (Sheet 2 of 2) 85

(J20-16) J30 28

(J20-11) J30 23

(J20-8) J30 20 BOOT-CNTRL C164 220pF RXD TP110

(J20-12) J30 24 TXD

(J20-4) J30 17 EXT_SPKR+

C207 220pF VR123 5.6V

(J20-7) J30 19 EXT_MIC VR112 5.6V C179 220pF P101-7 P101-3 P102-4 PTT

VR118 5.6V C189 1uF R224 100K P102-16 P102-17 C104 1uF VR113 5.6V VAG C165 220pF EXT_MIC R225 10K C190 680pF 6 5 C191 220pF 7 U107-2 MC33072 9.6V VRS_TX*_RX R110 15K P101-9 5V C107 220pF R112 100K C108 R113

.1uF 100K BUSYIN BUSYOUT RESET

(J20-9) J30 21

(J40-13)

(J40-20)

(J20-1)

(J20-10)

(J20-13)

(J20-19)

(J20-20) J30 J30 4 5 16 J30 J30 22 J30 25 J30 29 J30 30 TP101 R108 68K P101-1 5V

(J40-25) J30 10 PROG_SENSE C109 220pF VR121 5.6V R111 27K R115 75K C105 0.1uF RX_FIL_AUD 9.6V TP102 R114 330K C111 220pF C145 1000pF TP112 R109 100K URX_SND

(J40-22) J30 7

(J40-28) J30 11

(J40-1) J30 J30 1 2

(J40-21) J30 6 SNGL_TX_DATA

(J40-29) J30 12 SNGL_DET

(J40-24) J30 9 TEST_MODE-IN

(J40-23) J30 8 TONES-MOBILE_AUD SW7.5V P102-1 5V P102-3 C175 220pF VR115 15V C161 220pF VR102 5.6V 5V DNP R101 68K Q100 MMBT3904 R102 10K C100 220pF U103-2 4 3 MC14106 U100-2 R118 7 4.7K R117 4.7K MC33072 5 6 C101 33pF C113 2200pF R221 22K C194 1000pF R220 0 C188 220pF TP121 TP122 TP123 TP124 2 3 U107-1 1 MC33072 5V C112 220pF R138 4.7K Q103 MMBT3904 C122 220pF R136 10K C183 1uF R137 10K R213 4.7K C103 1uF T1 6 5 4 1 3 U103-5 10 11 MC14106 5V R211 10K R212 10K Q110 MMBT3904 R210 1K C202 220pF R200 4.7K U103-3 6 5 9.6V MC14106 R107 6.8K U102-2 MC14053B 11 5V 9 12 13 R155 10K 14 5 3 4 R139 1K C146 220pF R140 4.7K R104 100 R105 100 R106 4.7K 5V C102 220pF Q101 MMBT3904 5V Q104 MMBT3906 U101-2 MC14053B 11 12 13 Q113 SW7.5V 14 7.5V D S G C203 220pF R217 1K Q112 MMBT3904 C204 220pF Q111 MMBT3904 C205 220pF C182 10uF 3 2 U100-1 1 MC33072 R116 30K R119 6.8K C115

.01uF R121 10K R120 10K C114

.01uF U124-3 8 MC3303 9 10 C116

.01uF R122 27K R215 27K R216 1.5MEG C117

.015uF R123 27K U124-2 7 MC3303 6 5 C118 1000pF R124 C120 10K 0.1uF R125 56K D100 D101 C119 0.22uF C180 1000pF R172 10K U102-3 MC14053B VAG C121 100pF 12 13 U124-4 14 MC3303 R127 10K SNGL_OUT R175 10K 5V R126 15K TP104 3 2 U124-1 1 MC3303 TP103 R173 10K R171 47.5K 1%

R128 100K 1%

R129 27.4K 1%

R174 27.4K 1%

R130 22.1K 1%

R131 100K 1%

6 3 7 2 8 1 S1 S1 S1 9.6V C206 220pF R156 1K C125 220pF R166 4.7K A B C D E F G H I J

(J40-2) J30 3

(J20-14) J30 26 RSS

(J20-15) J30 27 TX_RX_AUDI O TP120 TP111 TP113 86 VRS750 Vehicular Repeater System Printed Circuit Board Schematic Diagram (Sheet 1 of 2) A B C D E F G H R142 1K C123 220pF R141 4.7K 5V Q102 MMBT3906 R143 4.7K R180 4.7K MC14053B U105-3 3 5 4 9 R181 4.7K U105-2 MC14053B 13 12 14 11 5V 9.6V 9.6V 9.6V 8 POWER U100 4 C139 220pF C140 0.1uF 16 POWER U101-4 6 7 8 C195 220pF C196 0.1uF 16 POWER U102-4 7 6 8 C142 220pF C143

.1uF C197 220pF C198 0.1uF 9.6V 4 POWER U104-5 11 C172 220pF C171 0.1uF 5V 14 POWER U103-7 7 9.6V P101 IS 18 PIN PROGRAMMING CONNECTOR P102 IS 25 PIN DB25 CONNECTOR BUS+

P102-5 C126 220pF VR103 5.6V C127 220pF VR104 5.6V BUS-

P102-14 AUX_RX_AUD P102-7 TP106 TP107 9.6V 16 POWER U105-4 6 7 8 C199 220pF C200 0.1uF C167 220pF C168 0.1uF 4 POWER U124-5 11 C141

.01uF C170 220pF RADIO_SWB+

SWB+

F100 VR110 15V C138 220pF MOB_ANA_GND L101 1000uH C137 2200uF 15 D102 P31 P32 P33 U103-1 2 1 MC14106 U103-6 12 13 MC14106 MC14053B U102-1 10 1 2 9.6V R226 4.7K 5V 9.6V R132 4.7K Q109 MMBT3904 1 2 R227 4.7K C173 220pF R165 2K MC14053B U105-1 15 TP114 J30 13

(J40-30) 10 Q115 MMBT3904 R229 10K R133 4.7K RX_FIL_AUD C208 220pF R228 10K R145 47K VAG C124 220pF R146 20K 9 10 U104-3 8 MC3303 MC14053B U101-1 MC14053B U101-3 R148 20K U104-4 14 EXT_MIC 15 1 2 4 SNGL_OUT 3 5 R150 MC3303 R151 20K 100K 10 9 9.6V VRS_TX*_RX R184 4.7K U104-1 1 MC3303 2 3 C160 220pF TP108 R147 4.7K TP105 C128 220pF VR105 5.6V CONNECTIONS TO TRANSCEIVER BUSY P102-23 C129 220pF VR106 5.6V RADIO_SWB+

TP125 TP126 TP127 TP128 C130 220pF VR107 5.6V SWB+

P102-22 RADIO_RESET P102-19 C132 1uF T2 6 5 4 1 3 R149 56K C134 0.1uF VAG C158 220pF C133 1uF 13 12 VAG TX_AUDIO P102-8 C131 220pF VR108 5.6V DGND P102-18 C151 10uF TP109 5 4 IN OUT U118 LT1129CQ SHDN*

ADJ 1 2 GND 3 TAB 6 C154 220pF MOBILE_MIC_HI C166 220pF C185

.047uF P102-12 MOB_ANA_GND P102-2 P102-11 P102-21 P102-10 C135 0.1uF FIL_AUD P102-6 C136 220pF VR109 5.6V R160 15K R163 10K TP119 SWB+

5V TP118 R157 15K Q106 MMBT3904 I J Q114 MMBT3904 C184 220pF R183 10K R182 1K MIC_FIL_SEL J30 15 C156 100uF C157 220pF GND2 8 VIN 7 6 5 GND3 NC1 VOUT 1 U111 GND 2 GND1 3 NC 4 C159 220pF C162 100uF C201 220pF W102 1 W102 2 W102 3 TP116 R161 820 C153 10uF C152 220pF 9.6V VAG R162 10K R164 10K C155 10uF TP117 7.5V SWB+

IN U129 LM317 ADJ OUT R158 360 C150 220pF R159 1.8K C148 1uF C149 10uF C147 220pF 9.6V 8 POWER U107 4 SW7.5V W101 1 2 3 4 5 VRS750 Vehicular Repeater System Printed Circuit Board Schematic Diagram (Sheet 2 of 2) 87 VRS750 Vehicular Repeater System Exploded View Parts List ITEM NO. MOTOROLA PART NUMBER DESCRIPTION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 1505764X01 3205931V02 1505905V02 2805347X01 4205395X01 3205789X01 3385950D01 1505784W01 1505791W01 3285803D01 PLN7780A 0310907A20 320545Z03 0410057A13 1483820M02 PMLD4196A PMLE4242A PMLE4243A 2885170D01 3085166D01 4285033D01 0300139800 0200844628 4285168D01 1485171D01 8485177D01 2785032D01 3205934V01 4205938V01 3885558D01 3285169D01 0785588D01 3205935V01 0305760W02 0400135783 0490440S01 0312002B14 COVER ASSEMBLY, Midpwr Top GASKET, Front Cover HOUSING, Remote Front CONNECTOR, 18 Position RETAINER, Programming Connector GASKET, Remote Cable LABEL, Front HOUSING, Programming Connector HOUSING, Programming Connector Terminal PLUG, Programming Connector VRS750 Controller Board SCREW, M3 x .5 x 10 (8 reqd) GASKET, Antenna Connector WASHER, Nylon (for Regulator) INSULATOR, Nylon, Heat Conductive

(for Regulator) TRANSCEIVER VHF Transceiver UHF R1 Transceiver UHF R2 Transceiver PLUG, RF Phone to SMB CABLE, RF Coax RETAINER, Internal Radio (2 reqd) SCREW, 6-32 x .5 NUT, 6-32 RETAINER, Flex Connector INSULATOR, PC Board CABLE, Flex CHASSIS, Modied GASKET, Casting CLIP, Spring PLUG, Plastic DC SEAL, Power BRACKET, Sp. Mounting GASKET, 25-Pin Connector SCREW, M5 x 0.8 x 12 (2 reqd) WASHER, Lk. Splt. (2 reqd) WASHER, Flat (2 reqd) SCREW, 10-16 x 1 (4 reqd) 88 VRS750 Vehicular Repeater System Exploded View and Exploded View Parts List VRS-to-Mobile Cable HKN6153A VRS-to-Siren Cable HKN6154A Pin Number Pin Number VRS750 P102 ASTRO Spectra Mobile DB25 Female Signal Name VRS750 P102 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 2 5 6 7 8 10 11 12 14 18 19 21 22 23 N/C FIL_Audio_GND N/C N/C Bus+

FLT_Audio Rx_Audio Tx_Audio N/C AGND Mic_Lo Mic_Hi N/C Bus-

N/C N/C N/C DGND Reset N/C Bus_GND SWB+

Busy N/C N/C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Siren

(HLN1439A) 39 pin J1 15 17 9 33 3 11 14 27 25 19 4 18 6 5 Signal Name N/C FIL_Audio_GND N/C N/C Bus+

FLT_Audio Rx_Audio Tx_Audio N/C AGND Mic_Lo Mic_Hi N/C Bus-

N/C N/C N/C DGND Reset N/C Bus_GND SWB+

Busy N/C N/C 89 VRS750 Programming Cable 3085031D01 VRS750 Programming Cable 3085031D01 VRS750 Programming Cable 3085031D01 Pin Number VRS750 P101 SRIB DB25 Female Signal Name Pin Number VRS750 P101 SRIB DB25 Female Signal Name 1 2 3 4 5 6 7 8 9 1 16 15 2 Ground N/C Boot_Cntl N/C N/C N/C TXD N/C Prog_Sense 10 11 12 13 14 15 16 17 18 N/C N/C N/C N/C N/C N/C N/C N/C N/C VRS750 Programming Cable Schematic (3085031D01) VRS750 Flashing Adapter Schematic (NTN4056A) 90 REPLACEMENT PARTS ORDERING ORDERING INFORMATION When ordering replacement parts or equipment information, the complete identication number should be included. This applies to all components, kits, and chassis. If the component part number is not known, the order should include the number of the chassis or kit of which it is a part, and sufcient description of the desired component to identify it. Crystal and channel element orders should specify the crystal type or channel element type number, crystal and carrier frequency, and the model number in which the part is used. MAIL ORDERS Send written orders to the following addresses:

Replacement Parts/

Test Equipment/Manuals/

Crystal Service Items:

Motorola Inc. United States and Canada Accessories and Aftermarket Division Attention: Order Processing 1313 E. Algonquin Road Schaumburg, IL 60196 Federal Government Orders:

International Orders:

Motorola Inc. United States and Canada Accessories and Aftermarket Division Attention: Order Processing 7230 Parkway Drive Landover, MD 21076 Motorola Inc. United States and Canada Accessories and Aftermarket Division Attention: International Order Processing 1313 E. Algonquin Road Schaumburg, IL 60196 TELEPHONE ORDERS United States and Canada Accessories and Aftermarket Division:

Call:

1-800-422-4210 1-800-826-1913 (For Federal Government Orders) 1-847-538-8023 (International Orders) FAX ORDERS United States and Canada Accessories and Aftermarket Division:

FAX:

847-538-8198 (Domestic) 847-576-3023 (International) 847-538-8194 Parts ID:

Servicers Training (VHS Video Tapes):

Call:

847-576-2828 Federal Government Orders:

FAX:

International:

410-712-4991 410-712-6200 PARTS CUSTOMER SERVICE PRODUCT CUSTOMER SERVICE United States and Canada Accessories and Aftermarket Division:

Call: 1-800-422-4210 Parts Identication:

Call: 847-538-0021 Customer Resource Product Support

(Sales and Service Assistance):

Call: 1-800-927-2744 FAX: 1-954-723-4800 91 6881094C84 72 Motorola 8000 West Sunrise Boulevard Fort Lauderdale, Florida 33322

 

 

ASTRO Spectra Compatible VRS Model 750 (136-174 MHz) ASTRO Spectra Compatible VRS Model 750 (403-470 MHz) ASTRO Spectra Compatible VRS Model 750 (450-512 MHz) Description Description P2082A X X X X X Item Number HHN4044A VRS 750 Housing HLN6855A VRS 750 Mounting Assembly PLN7780A VRS 750 Controller Board HLN6856A XCVR Hardware PUD1001A VHF Transceiver PUE1036A UHF R1 Transceiver PUE1037A UHF R2 Transceiver PRELIMINARY USERS MANUAL Model Chart for the Vehicular Repeater System Model 750 Model Number P2080A P2081A X X X X X X X X X X Note 1 Note 1 HKN6153A Cable, Mobile-to-VRS Note 1 Note 2 Note 2 HKN6154A Cable, Siren-to-VRS Note 2 6881094C84 VRS 750 Detailed Service Manual Note 3 Note 3 Note 3 6881087C79 Safety Pamphlet X X 2884606M01 Mini-UHF crimp connector X X 3305873U04 Chassis Label X X X X X X X X 3085031D02 Cable, VRS Programming (optional) NTN4056A Adapter, VRS Flash programming (optional) NKN6460A y-cable kit for dual controlhead w/vrs (optional) TLN5277B DC filter for excessive alternator whine (optional) With option xxxxA Note 1 With option xxxxB Note 2 One item per 10 units Note 3 Global Tuning Tool - CD ROM (optional) Front Label XCVR Label Packing Kit X X X X X X VRS750 SPECIFICATIONS- VHF GENERAL Model: P2080A (136 174 MHz) RF Power Out:

TRANSMITTER RECEIVER Intermodulation per EIA:

Number of Channels: 1, T1=R1 275 mW to 2 W tunable 70 dB Frequency:

Programmable, Synthesized Frequency Channel Channel Spacing:

12.5/20/25 kHz Operation Temp. Range:

Spurious and Harmonic Emissions:

Hum and Noise:

-36 dBm < 1 GHz

-30 dBm > 1 GHz Frequency Stability:

2.5 ppm @ 25 kHz 2.5 ppm @ 12.5 kHz Modulation Limiting(max): Conducted Spurious Rejection:

-40dBm @ 25 kHz

-35dBm @ 12.5 kHz Reference Sensitivity(typical):

0.28V (-118dBm) at 12 dB SINAD

-30C to +60C Primary Power:

13.8 VDC 20%, Negative Ground 2.5 kHz @ 12.5 kHz 4.0 kHz @ 20 kHz 5.0 kHz @ 25 kHz 70 dB DC Current Drain(max):

120mA Receive 500mA Transmit @ 275mW 1.10A Transmit @2W Squelch Operation:Private-Line required for repeater access Duty Cycle: Intermittent per EIA at 275mW PPI Sample time: 16ms Typical Audio Response: (from 6dB/octave pre-emphasis, 300 to 3000 Hz)

+1, -3 dB Audio Distortion:

3% Typical @ 1 kHz, 60%

maximum deviation FM Hum and Noise: -40dB TX Attack Time: 32 ms Typical Adjacent Channel Selectivity:

60 dB @ 12.5 kHz 70 dB @ 25/30 kHz Audio Response (0.3 3 kHz):

+1 to 3 dB Audio Distortion 3% Typical @ Mobile Rated Audio*

Conducted Spurious Emissions:

Singletone Encoder/Decoder:

Antenna Impedance: 50 ohms -57dBm <1GHz

-47dBm > 1GHz Nominal 847.5 Hz FCC Identifiers:

AZ492FT3802 (P2080A) Industry Canada:

* Typically 5W in 8 ohms Antenna connector: mini-uhf RX Attack Time: 60ms Typical VRS750 SPECIFICATIONS-UHF GENERAL Model: P2081A (403 470 MHz) P2082A (450 512 MHz) Number of Channels: 1, T1=R1 TRANSMITTER RF Power Out:

275 mW to 2 W tunable RECEIVER Intermodulation per EIA:

70 dB Frequency:

Programmable, Synthesized Frequency Channel Channel Spacing:

12.5/20/25 kHz Operation Temp. Range:

-30C to +60C Primary Power:

13.8 VDC 20%, Negative Ground Spurious and Harmonic Emissions:

Hum and Noise:

-36 dBm < 1 GHz

-30 dBm > 1 GHz Frequency Stability:

2.5 ppm @ 25 kHz 2.5 ppm @ 12.5 kHz Modulation Limiting(max):

2.5 kHz @ 12.5 kHz 4.0 kHz @ 20 kHz 5.0 kHz @ 25 kHz

-40dBm @ 25 kHz

-35dBm @ 12.5 kHz Reference Sensitivity(typical):

0.28V (-118dBm) at 12 dB SINAD Conducted Spurious Rejection:

70 dB DC Current Drain(max):

120mA Receive 700mA Transmit @ 275mW 1.20A Transmit @2W Squelch Operation: Private-Line required for repeater access Duty Cycle: Intermittent per EIA at 275mW Audio Response: (from 6dB/octave pre-emphasis, 300 to 3000 Hz)

+1, -3 dB Audio Distortion:

3% Typical @ 1 kHz, 60%

maximum deviation FM Hum and Noise: -40dB Adjacent Channel Selectivity:

60 dB @ 12.5 kHz 70 dB @ 25/30 kHz Audio Response (0.3 3 kHz):

+1 to 3 dB Audio Distortion 3% Typical @ Mobile Rated Audio*

TX Attack Time: 14 ms Typical PPI Sample time: 16ms Typical Conducted Spurious Emissions:

Singletone Encoder/Decoder:

Antenna Impedance: 50 ohms

-57dBm <1GHz

-47dBm > 1GHz Nominal 847.5 Hz FCC Identifiers:

AZ492FT4848 (P2081A) AZ492FT4849 (P2082A) Industry Canada:

Antenna connector: mini-uhf RX Attack Time: 60ms Typical

* Typically 5W in 8 ohms List of Abbreviations and Acronyms B-P CPS DPL HT750 HUB ICM ms PAC PL PPI P-B RF RX SB SBEP Slm-net TOT TX VIP VRS VRS-EP VRS750 Base to Portable Customer Programming Software Digital Private Line Transceiver internal to VRS750 Hang Up Box In Car Monitor Millisecond Portable Area Coverage Private Line Portable Priority Interrupt Portable to Base Radio Frequency Receive Serial Bus Serial Bus Expanded Protocol Transceiver internal to VRS-EP Time Out Timer Transmit Vehicle Interface Port Vehicular Repeater System Vehicular Repeater System - Expanded Protocol Vehicular Repeater System - Model 750 1. Introduction Description The ASTRO Spectra compatible Vehicular Repeater System - Model 750 (VRS750) is a mobile radio system component that provides on-site repeater capability between a portable radio and a base station. The VRS gives the portable user the equivalent range of a mobile radio with the flexibility of a portable. The VRS is not an ASTRO-capable radio; instead, it is designed to interface with an ASTRO Spectra mobile radio. It can only transmit and receive clear analog transmissions. The VRS receives transmissions on the portable radio's transmit frequency with the proper access PL, and passes these portable signals to the mobile radio. The mobile radio re-transmits the signals to the base station on the mobile radio's transmit frequency. NOTE: These transmissions have the mobile's ID, not the portable's. Similarly, base station signals received by the mobile radio are sent to the VRS and re-

transmitted to the portable radio. The VRS does not provide local repeater capability

(received portable signals are not repeated on the portable receive frequency). The VRS-to-portable and portable-to-VRS communications are limited to clear analog only. This is a simplex-only interface; the VRS cannot receive and transmit simultaneously. The base station-to-mobile and mobile-to-base communications protocol is not limited to analog only. Rather, this interface is limited by the features and functions of the ASTRO Spectra and the base. Ordering Information The VRS is a crossband repeater that operates on either UHF or VHF frequencies. The repeater cannot be operated with a mobile radio operating in the same band as the VRS unit. The VRS RF platform is based on the HT750 synthesized transceiver. The VRS supports one channel whose frequency and channel spacing can be programmed in the field. The VRS remains a simplex repeater and as a result, the transmit frequency must be set equal to the receive frequency. The VRS receives its programming information from the ASTRO Spectra mobile at power-up. The ASTRO Spectra mobile supports the VRS programming fields via ASTRO Customer Programming Software (CPS). For more information, refer to Programming, Chapter ?. The VRS is not compatible with ASTRO Spectra mobiles with the VSELP signaling type. When integrating a VRS with an ASTRO mobile with a Siren/PA, an additional interface cable is needed (?). This cable allows the VRS to be connected to the Siren/PA. For more information, refer to "Installation," Chapter 4. When integrating a VRS with an ASTRO mobile with Dual Control heads, an additional interface cable is needed (NKN6460A). This y-cable allows the VRS to be connected to the ASTRO mobile with two control heads. For more information, refer to "Installation,"

Chapter 4. A separate antenna (not included) is necessary for use with the repeater. Typically, a one-

quarter (1/4) wave length antenna maximizes radiation efficiency when installed at the center of the vehicle roof. If it is necessary to mount the antenna on the vehicles trunk lid, an appropriate 3dB gain antenna should be used. See "Installation," Chapter 4, for details. A filter for the battery lines (TLN5277B)is available for use with ASTRO Spectra mobiles. This filter can be used to prevent excessive alternator whine noise from being heard on the mobile speaker during VRS operation. The VRS ships from the factory with the low output power setting at 275mW and a high output power setting of 2W. The low output power setting is the default setting. We recommend the LOW Transmit Power setting of 275mW for optimal performance. This output power provides the VRS with a similar range as the portable when attached to a mobile antenna. Any deviation from this setting could result in a loss of communication from the portable to the base. The Global Tuning Tool (not included) can be used to tune the VRS output power in the field. For more information refer to Tuning, Chapter ?. VRS Features The VRS operates with the ASTRO mobile radio and contains the following integrated features:

o o o o o o o o transmission from the portable radio. o o o All VRS features can be programmed in the field using ASTRO Spectra mobile CPS. For more information, refer to Programming, Chapter ?. IMPORTANT NOTE: All ASTRO Spectra VRS systems with the same VRS RF transmit/receive frequency need to be CPS programmed identically to ensure proper operation. Failure to do so could result in erratic system operation. The VRS does not have to be installed in the system for programming - only the mobile radio is programmed. If the VRS is not connected after programming the mobile system, an error message "ERR 12/10" will be displayed on the control head. Automatic, multiple-unit, priority-resolution algorithm. Portable priority interrupt (PPI) function. Conventional/trunked operation. Remote switch enable/disable capability for control charger interface. Remote activation of emergency alarm feature. In-car monitor operation. VRS mobile access tones. Mobile radio transmitter steering of up to eight modes via Private-Line (PL) code TX PL generator. Base repeater operation for two-frequency, simplex, fixed-repeater systems. Mobile audio repeat. Mutually-Exclusive Features The VRS IS NOT compatible with the following mobile radio features:

o W3 Control Head is not supported with VRS o VSELP signaling type o Data-VRS and data are not compatible on the same channel and cannot be used simultaneously. VRS should never be activated on a channel that has packet data enabled, and VRS mode steering channels should not have packet data enabled. o Scan o Over-the-Air Rekeying (OTAR) Rekey Request o Message (from the Control Head)-Trunking or Conventional o Status (from the Control Head)-Trunking or Conventional o Emergency Call-Trunking or Conventional-Emergency Call and VRS are mutually exclusive. Even if the mobile is programmed for Alarm and Call, when the Alarm case is exited, the mobile will not transition into Emergency Call while the VRS is activated. Likewise, if the mobile is in Emergency Call, the VRS cannot be activated. NOTE:When an Emergency Alarm is received, the dispatcher may elevate that talkgroup to Emergency status. o Reprogram Request-Trunking o Repeater Access Control-Conventional o Mobile Single Tone-Conventional o Seven-Tone Modat-Conventional o Motorcycle o Consolette (Digital Remote and Tone Remote) The following mobile radio features may be received but may not be initiated or responded to while VRS is enabled. o Private Conversation -Trunking o Call Alert-Trunking or Conventional o Telephone Interconnect-Trunking or Conventional o Voice Selective Call-Conventional 2. VRS Operation General The VRS is a crossband repeater that repeats either UHF or VHF portable transmissions though a VHF, UHF, or 800MHz ASTRO mobile. The repeater cannot be operated with a mobile radio operating in the same band as the VRS unit. In multiple-VRS sites, the VRS uses a priority algorithm to prevent other VRS units from repeating. In this mode, only the highest priority VRS will serve multiple portable users. This prevents interference problems associated with multiple VRS units in proximity to one another. Control Unit The VRS may be enabled/disabled from the ASTRO mobile radio's remote-mounted W4, W5, W7, or W9 control head (see Figure 1). The VRS button may occupy any of the indicator button positions. Field programming determines the exact position. The VRS requires an ASTRO radio with a remote-mount control head. Figure 1 Typical ASTRO Control Head with VRS When the VRS is turned on, the indicator illuminates and, after transmitting the Single Tone burst, the words "VRS BOTH" (indicating the In-Car Monitor mode) will be displayed momentarily. The indicator remains on for as long as the VRS is on. When the VRS unit is activated, it transmits Single Tone on the portable frequency, and assumes the priority (active) repeater state. The Single Tone frequency is fixed at 847.5 Hz. For proper operation, all VRS units to be used in the same system must be programmed with the same Single Tone frequency, as well as other VRS and ASTRO mobile features. Press the VRS button to disable the VRS option. When the system is turned off and then back on from the control head, the VRS option returns to the state it was in immediately before the control head was turned off. Vehicle Interface Ports Another method of enabling/disabling the VRS option is through the use of a vehicle interface port (VIP). The field programmer selects which VIP to use and whether the input control voltage is to be high/ground or ground/high. One use of VIP operation connects the VRS switch lead to a portable radio vehicular control charger, such as the AVA, SVA, MVA, or MTVA. Remove the portable from its charger pocket to automatically enable the VRS option. Replace the portable unit in its charger to disable the VRS option. A toggle switch on the portable unit charger allows the portable unit to be removed without enabling the VRS option. NOTE:

included with the VRS. Turning the portable unit charger off, then on does not disable the VRS option. The VIP setting controls the on/off state of the VRS option. If the field programmer chooses the VIP option, pressing the VRS button on the control head will only cause the display to change momentarily to the In Car Monitor Mode ("VRS BOTH"). It will not enable or disable the VRS as previously described. It is still necessary, however, to select in CPSCPS an indicator button for the VRS if it is desired to have the indicator light when the VRS is enabled. VRS Access With the VRS on, press the portable radio's PTT button to begin transmissions. The VRS programming must include correct PL frequencies to allow the portable unit to access the option. The VRS option receives signals with the correct PL, then uses the mobile radio to re-transmit the signals. The control head's XMIT indicator lights during the re-transmission. The VRS re-transmits received mobile signals as explained in the "Mobile Audio Repeat"

paragraph on page 7. Note that the XMIT indicator does not light when the VRS is transmitting to the portable. To transmit directly to the other portable units, turn off the portable transmit PL. This allows you to talk around the VRS without transmitting on the mobile channels. This requires an additional field modification kit, PLN1334A, which is not In-Car Monitor The "In-Car Monitor" (ICM) feature is for use in a two-man operation where one user

(user 1) is out of the vehicle while the other (user 2) remains in the vehicle. This allows user 2 limited access to both mobile and portable communications when the VRS is on, even when the repeater is the priority unit. ICM operation is set to BOTH. ICM Transmissions VRS BASE:

Press the mobile's PTT to transmit on the frequency corresponding to the mode shown on the control heads display. If this mobiles VRS is the priority unit (in delay state zero), the VRS unit will then become non-priority upon the mobile PTT. If you press the mobile's PTT during portable-to-base VRS activity, a talk-prohibit tone sounds and the mic audio is disabled. VRS BOTH:

Press the mobile's PTT to transmit simultaneously on the frequency corresponding to the mode shown on the control head's display, and the portable frequency. Use the ASTRO CPS to enable the VRS TX PL generator option to transmit with the proper PL frequency. If you press the mobile's PTT during portable-to-base VRS activity, a momentary talk-

prohibit tone sounds and the microphone audio is disabled. When using VRS BASE or VRS BOTH mode, all mobile transmissions are on the mode that is shown on the control head's display. If the VRS is currently steering to another mode, that steered mode will be displayed on the control head. Any mobile transmissions will be on that new mode until the portable steers the VRS back or the mode rocker switch is used to change modes. If the mode rocker switch is used to change modes, the portable user will not be made aware of this mode change. With Ack Tones are enabled, the portable user will hear a "bad" tone if the mode is changed during the transmission. VRS Reception The VRS option has no effect on mobile radio squelch control or normal mobile radio reception. The VRS portable unit's squelch setting is not user adjustable. Portable audio is heard from the mobile speaker of the priority VRS unit as shown in the following table:

Mobile Microphone Portable Audio Heard from Mobile Speaker On HUB Off HUB

* = any valid repeater access PL Repeated portable transmissions will always be heard from the mobile speakers. Portable transmissions without proper PL will only be heard from the mobile speaker if the microphone is off HUB. Mobile Audio Repeat The VRS transmits to the portable when audio unmutes the mobile speaker. This allows the user to set the monitor button "on" to defeat the coded squelch requirements of the mobile radio on a base-to-portable transmission or "off" to prevent the VRS from PL*

CSQ repeating base-to-portable (HUB will also disable this), unless the coded squelch requirements of the mobile radio are met. Button presses (that is, Volume, Mode, etc.) on the priority mobile unit will also be transmitted by the VRS. 3. Operation of VRS Options The following sections describe the operation of CPS field-programmable options of the VRS. This includes information about when to use an option and compatibility between options. Base Repeater For two-frequency simplex systems using a fixed-site repeater, you can enable the base repeater option. This adds 300 ms of delay to the prioritization routine to account for the fixed repeater attack time. This allows non-priority mobiles to detect any priority mobile in the system through the base repeater. Mobile Detector The Mobile Detector feature allows the user to operate VRS units with two-frequency simplex dispatch systems without a base repeater. This feature allows the automatic multi-unit priority resolution algorithm to function in the above scenario. When this feature is activated by the CPS, a non-priority VRS will send a message to the mobile to enable a "Listen Around" feature when a proper portable PL is received.

"Listen Around" switches the mobile radio's receive frequency to match that of its transmit frequency of the steered mode. The non-priority VRS will count down in priority if its corresponding mobile does not detect the repeated transmission on the "Listen Around" frequency. When the portable is dekeyed, the non-priority VRS will send a second message to the mobile to disable "Listen Around" and return to normal operation. This feature does not use any additional user modes in the mobile. NOTE:

modes will be unaffected. VRS Transmit PL Generator The transmit PL generator, when enabled, causes the VRS to transmit (base-to-portable), with specific field programmable PL tones. The selected VRS transmit PL frequency cannot be the same as any of the VRS receive PL frequencies that the portable uses to access the vehicular repeater. VRS Mode Steering The VRS steering option gives the portable operator the ability to select the current mobile radio mode via PL tones. The total number of Mode-Steered modes can not exceed eight (including emergency, message, and status). The operator may program as many as eight such tones, along with corresponding mobile mode numbers, into the The Mobile Detector feature only works on conventional modes. Trunked If mode steering is not selected during CPS programming, the programmer VRS. The portable operator sets the channel or mode select switch to the position corresponding to the desired mobile mode and keys up the portable. The VRS unit decodes the PL tone and steers the mobile radio to the desired mode. There are two types of steering supported: Transmitter Steering/Receiver Latching, and Transmitter Steering/Receiver Steering. NOTE:

will need to enter the repeater access PL, which corresponds to a single access PL with select mode steering. Steering Types o

<Transmitter Steering/Receiver Latching> - On portable-to-base repeating, the mobile radio is steered to the proper mode as determined by the received PL from the portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio remains on this mode. Thus, all future base-to-portable repeating is heard via the mobile mode last steered by the portable. this operation and while no repeat is occurring, the ICM user keys the mobile with the micropnone's PTT button, the mobile will now transmit on the latched mode that is displayed on the control head. If, however, the in-car-monitor (ICM) user changes the selected mode using the mobile's mode rocker switch before pressing the mic PTT, the mobile will now transmit on the new selected mode. NOTE:

to the selected user mode on the control head by programming one PL destination for Sel-Mode. However, the selected mode can be changed by the rocker mode switch. o

<Transmitter Steering/Receiver Steering> - On portable-to-base repeating, the mobile radio is steered to the proper mode as determined by the received PL from the portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio remains on this mode for 6 seconds. During this 6 seconds, the VRS waits for a repeatable base-to-portable transmission to be received. The mobile control head will display the steered/latched mode. If, sometime after For the above type of steering, the portable user will be able to steer back If a base-to-portable transmission is not received, the mobile will return to the last mode selected by the control head's rocker switch (current user-selected mode). If a base-to-portable transmission is received during the 6-second timer, the timer will be reset back to 6 seconds and start over at the end of the transmission. If the portable is keyed during the 6 seconds, the VRS will handle the destination PL accordingly and reset the timer. If the 6-second timer has not expired, no repeat is occurring, and the ICM user keys the mobile with a microphone PTT, the mobile will transmit on the steered mode and the 6-second timer will start over at the end of the transmission. Steering Destination Types There are five types of actions, or "steering destination types," that the VRS can be programmed to perform as a result of receiving a portable transmission with the specified PL:

Each receive PL can only be used once and can only be programmed with NOTE:

one type of steering destination (for example, a single PL cannot be programmed to both change the mobile mode and send a message.) Zone/Chan The VRS will command the ASTRO mobile to change to the mode programmed by the CPS. Once the mobile has steered, it will follow the conventions of the type of steering selected (for example, Transmitter Steering/Receiver Latching). Select Mode The VRS will command the ASTRO mobile to return to the last mode selected by the rocker switch on the control head. If the portable user has steered to another mode, and the selected mode is changed in the car, the steering will be canceled until the VRS receives another mode steering PL. Emergency Alarm The VRS will initiate an Emergency Alarm through the ASTRO mobile, if the mobile is programmed for this type of Emergency, in the same manner as if the Emergency button on the control head were pressed. The type of Emergency (trunked or conventional) depends on the currently selected mobile mode, (trunked or conventional, respectively). The VRS will only generate an Emergency, not perform a portable-to-base audio repeat, while the portable is transmitting on an "Emergency request" channel. This feature is typically implemented in the portable, using a one-touch button that has been programmed for Emergency-revert to a channel with the proper PL. Although the portable generates MDC tones, the VRS cannot decode MDC. Instead it responds to the PL of the portable mode on which the Emergency MDC tones are transmitted. All of this is transparent to the user. Message The VRS will command the ASTRO mobile to send out an CPS-programmed message on the mode currently displayed on the control head, in the same manner as if the request to send a message had been generated using the control head. The VRS will send out only one message per received portable signal. No mode steering will occur; the currently steered/latched mode and the selected mobile mode will remain as they were before the request to send a message was received. If the message selected is valid, the VRS will transmit to the portable the mobile tones indicating whether or not the valid message was acknowledged. If the message selected is invalid, (either incorrectly programmed in CPS or not a valid message for the currently displayed mode), the VRS will send a low-pitched alarm tone to the portable. To generate a message request, the portable user would:

o o o o The VRS will not perform a portable-to-base audio repeat while the portable is transmitting on a "message request" channel. NOTE:

activated. Status select the channel on the portable programmed for the message request, momentarily press the PTT button, wait for the confirmation tone, and return the channel selector to a voice channel. A message cannot be generated from the control head while the VRS is A status cannot be generated from the control head while the VRS is select the channel on the portable programmed for the status request, momentarily press the PTT button, wait for the confirmation tone, and return the channel selector to a voice channel. The VRS will command the ASTRO mobile to send out an CPS-programmed status on the mode currently displayed on the control head, in the same manner as if the request to send status had been generated using the control head. The VRS will send out only one status per received portable signal. No mode steering will occur; the currently steered/latched mode and the selected mobile mode will remain as they were before the request to send a status was received. If the status selected is valid, the VRS will transmit to the portable the mobile tones indicating whether or not the valid status was acknowledged. If the status selected is invalid, (either incorrectly programmed in CPS or not a valid status for the currently displayed mode), the VRS will send a low-pitched alarm tone to the portable. To generate a status request, the portable user would:

o o o o The VRS will not perform a portable-to-base audio repeat while the portable is transmitting on a "status request" channel. NOTE:

activated. Time-Out Timer The Time-out Timer (TOT) duration value sets the maximum allowable time for a base-

to-portable transmission. The VRS TOT may be set to 30, 60, 120 seconds, or disabled. When a unit times out, it counts up to delay state one. This removes it as the priority unit. VRS Single Tone When the VRS unit is enabled, it transmits an audible tone (Single Tone) for 700 mS which is used by other VRS units for the automatic prioritization routine. The Single Tone frequency is fixed at 847.5 Hz. VRS Mobile-TX Acknowledgment Tones (Conventional Only) When this option is enabled, the VRS transmits a 750 Hz feedback tone after it has received a repeatable message on the portable frequency. This signals the portable operator that the transmission was received. If the repeated message was cut short due to the mobile TOT being exceeded or the mobile channel being changed during the repeat, a lower-pitched tone (304 Hz) sounds. If the portable user does not hear a tone after completing a transmission, the portable is either out of range of the repeater or there is no priority repeater in the area. See "VRS Mobile Trunking Tones (Trunking Only)" on page 26 for a description of trunking acknowledgment tones. Flashing Display The Flashing Display feature causes the display on the control head to alternate between the current mode and "VRS BOTH." This feature is used primarily when the VRS enable/disable button does not have an indicator light or when VIP activation is used. This feature is normally disabled in CPS. The length of time "VRS BOTH" is displayed every 6 seconds is determined by the "temporary message display timer" value. This value (from 250 to 6250 ms [default = 1000 ms]) can be programmed by the CPS. It is in the RADIO WIDE DISPLAY OPTIONS screen (D, C, F from the main CPS screen). Repeater PPI The Repeater Portable Priority Interrupt (PPI), when enabled, causes a base-to-portable transmission to be interrupted every 1 second in trunked mode or 2 seconds in conventional mode so that the repeater can search for a portable radio signal. (These times are programmable and may be changed to 500ms for trunked or 500ms for conventional modes). This interruption may be heard on the portable as a "clicking"

noise, but PPI is necessary to give the portable user priority over base-to-portable transmissions, for the self-clearing function of the automatic priority resolution feature, and to allow portable users in trunked mode to break in during system hang time to prevent loss of voice channel. This feature may be disabled through CPS. Quick-Key This feature allows the portable user to determine the status of the mobile trunking system. The feature is initiated by a short press of the portable's PTT that is long enough for the VRS to key the mobile and access the trunking system, for less than 1 second in duration. 4. Installation When selecting the location for the VRS, make certain that there is sufficient clearance for routing the T-cable and the antenna cable to the front of the unit. VRS Installation The standard VRS is installed using the HKN6153A interface cable. The molded DB-25 end connects to the ASTRO front connector. The DB-25 end with the plastic jacket connects to the VRS (see Figure 2). Figure 2 Installing the VRS to an ASTRO Mobile If an external Siren/PA is to be used, the option xxxxAA must be ordered which replaces the HKN6153A cable with a HKN6154A cable, or a separate HKN6154A cable must be ordered. To install, plug the "T" side of the HKN6164A cable to the Siren/PA. Replace the mounting screw on the HKN4363B cable with the double length screw. Plug this side into the "T" cable. Plug the DB-25 end of the HKN6154A into the VRS (see Figure 3). Figure 3 Installing the VRS with an External Siren/PA Mobile Radio Operation and EME Exposure To assure optimal radio performance and that human exposure to radio frequency electromagnetic energy is within guidelines referenced earlier in this document, transmit only when people outside the vehicle are at least the minimum lateral distance away from Minimum Lateral Distance from Transmitting Antenna 8 Inches (20 Centimeters) a properly installed, externally-mounted antenna. Table ? lists the minimum lateral distance for the VRS 750:

Rated Power of Vehicle-installed Mobile Two-way Radio Less than 7 Watts VRS Antenna Installation Recommended mobile antenna installations are limited to metal body vehicles at the center of the roof and center of the trunk deck locations. Install the antenna to be used with the VRS according to the instructions supplied with it by the manufacturer (an antenna is not included with the VRS models). Mount the antenna as far from the mobile radio antenna as possible, but never less than three feet. An ideal configuration would be a roof-mounted mobile radio antenna and a trunk-

mounted VRS antenna. Connect the antenna cable mini-UHF connector to the antenna jack on the rear of the VRS unit. A mini-UHF crimp connector is provided with each VRS750 unit for easier installation with a pre-existing antenna. VRS750 Programming The user selectable operating parameters for the VRS750 reside in the ASTRO mobile EEPROM during normal operation. The EEPROM located in the VRS750 holds the tuning parameters. The VRS750 programming windows reside in ASTRO Spectra CPS and are accessible when the VRS-EP Option is enabled in CPS under the Radio Configuration->Radio Wide->Advanced window (see Figure 4). Figure 4 Advanced window (Radio Configuration->Radio Wide->Advanced) The VRS750 does not function without CPS programming and is not pre-programmed at the factory. To ensure operational compatibility from one unit to the next within the fleet, all of the ASTRO Mobile and VRS750/VRS-EP systems should be programmed the same way. Special Programming Notes The VRS button can be located in any of the indicator button positions normally used for option buttons. The VRS750 option can be enabled/disabled by a vehicle interface port (VIP). Use the VIP Control of VRS box in the Radio Configuration->Radio Wide->VRS window

(see Figure 6) to enable VIP control and to select whether the input control is active open or active closed. Then use the Radio Configuration->Radio Wide->Radio VIP window (see Figure 5) to select the VIP to be used. However, the VRS button must still be added to the control unit if it is desired to have the indicator light when the VRS750 is enabled. See the ASTRO Spectra CPS users manual for details concerning programming the VIP. Note: The ASTRO Spectra CPS users manual does not indicate that the VRS button is required to have the indicator light when the VIP is enabled. Figure 5 Radio VIP window (Radio Configuration->Radio Wide->Radio VIP) ASTRO VRS Programming Windows There are five windows for editing the VRS Option. Four of these windows are in the Radio Wide section of Radio Configuration while the fifth window is a table for the VRS mode steering PLs. The first window is the VRS subsection of the Radio Wide options (see Figure 6). In this window Base Repeater, Mobile Detector, Flashing Display, VIP control of VRS, and Trunking Access Tones can be enabled or disabled by clicking in the box to the left of the option. This window is also where the ICM mode can be selected using a pull down menu. Enabling Base Repeater will add 300ms of delay to the prioritization routine to account for fixed repeater attack time. Figure 6 VRS window (Radio Configuration->Radio Wide->VRS) The second window is the VRS Private Line subsection (see Figure 7). This window allows the user to select a Mode Steering type, if one is being used. If Mode Steering is set to Disabled, the Access PL Freq. and Access PL Code fields will become user selectable. These fields specify the one PL frequency transmitted by the portable that will be used to access the VRS750. The VRS750 will treat that access PL in the same manner as a select mode mode steering PL. To edit these fields click in the Access PL Freq. or Access PL Code box and use the pull down menu to select the desired frequency or code. Also located on the second window is the VRS Tx Squelch Type. To edit this field click in the box to the right and use the pull down menu to choose between TPL and CSQ. If TPL is selected, meaning that the VRS should transmit to the portable with PL, the VRS Tx PL Freq. and VRS Tx PL Code fields will become user selectable. To edit these fields, click in the VRS Tx PL Freq. or VRS Tx PL Code box and use the pull down menu to select the desired frequency or code. Figure 7 VRS Private Line window (Radio Configuration->Radio Wide->VRS Private Line) The third window is the VRS Advanced subsection (see Figure 8). This window is used to enable/disable the Access Acknowledgment and Time-Out-Timer Tones and Repeater Portable Priority Interrupt (PPI) as well as selecting the Time-Out-Timer duration. The Time-Out-Timer duration may be set to 30, 60, or 120 seconds, or infinite. The infinite setting should be used with caution, since damage to the transmitter could result from any extremely extended transmission. It should be noted that the Repeater PPI feature must be enabled to allow the multi-unit priority algorithm to function correctly when there will be multiple VRS units on scene. The time between interrupts may be set to Fast (500ms) or Slow (2 seconds) for conventional modes and Fast (500ms) or Slow (1 second) for trunked modes. Figure 8 VRS Advanced window (Radio Configuration->Radio Wide->VRS Advanced) The fourth window is the VRS Personality subsection (see Figure 9). The VRS Personality sets the VRS Frequency Band, Simplex Frequency, Channel Spacing, and TX Output Power for the VRS750. The VRS750 can be programmed for 12.5, 20, or 25 kHz Channel Spacing with a High or Low output power (factory power settings are 2W for High and 300mW for Low). Note that the VRS Personality will allow the Frequency Band to be set to VHF, UHF R1, or UHF R2 regardless of which model VRS750 is being used, but upon power up the error message VRS 001 will be displayed if the frequency band is incorrect. Note: Older VRS units, such as the VRS-EP, do not support any of the fields in the VRS Personality window. However, these fields can be programmed without having any effect on the VRS-EP, so that the VRS-EP and VRS750 can be interchangeable without reprogramming the mobile. Figure 9 VRS Personality window (Radio Configuration->Radio Wide->VRS Personality) The VRS Personality can be programmed directly into the VRS750 EEPROM using Professional Radio CPS and a new dip switch configuration (see Figure 10). All other operating parameters will still be programmed using the ASTRO Spectra CPS. Switch #

1 2 3 4 Position OFF ON ON Not Used Figure 10 VRS750 DIP switch settings The fifth window, Radio Configuration->Radio Wide VRS-EP Mode Steering->VRS-

EP Mode Steering List->VRS-EP Mode Steering - 1 (see Figure 11) is a table containing PL and mode steering information that can be edited. Mode Steering must first be enabled in the VRS Private Line window before the mode steering PLs in the table can be edited. To enter the PL codes used in mode steering and their corresponding destinations, enter the desired PL code or frequency by using the pull down menu in each PL Freq. or PL Code box. Then select the corresponding Steering Destination in the same manner. If the VRS Tx Squelch Type was set to TPL in the VRS Private Line window, none of the mode steering PLs may be the same as the VRS Tx PL Frequency. Note: The Receive PL filter internal to the VRS is a low pass filter with a -3 dB point of approximately 170 Hz. As a result, the PLs greater than 170 Hz will be attenuated to allow for a decreased decode sensitivity. The higher the PL frequency the greater the attenuation. The Emergency, Message, and Status features of the VRS are best suited for use with these higher PL frequencies. Figure 11 VRS-EP Mode Steering window Due to Host memory considerations, the maximum number of Zones allowed to be accessed by the VRS Mode Steering window is 20. Any Zone number greater than 20 will not be allowed in this window but is allowed for normal radio operation. VRS7 SRIB COM Port Connect to the PCs ASTRO Mobile VRS750 Global Tuner The Tuner for Professional Radios (Global Tuner) can be used to adjust the VRS750s Transmitter Output Power and Receiver Squelch Settings. In order to program the VRS750 using the Global Tuner it should be connected to the mobile and to a PC via its COM port as indicated in Figure 12. Figure 12 VRS connection to the PC Once the setup is complete and the mobile is turned on the current tuning parameters can be read from the VRS750 by selecting File->Read Radio Information and Softpots on the Global Tuner. Note: Radio Serial Number and Radio Model Number shown at the bottom of the screen will not match the model number and serial number of its associating VRS. To adjust the Transmitter Output Power select TX Align->Transmit Power->High (or Low) (see Figure 13). High and Low are associated with the VRS Output Power setting in the VRS Personality window of ASTRO CPS. This will bring up a window of seven test frequencies and their current softpot values. By increasing the softpot values the Tx Output Power will be increased up to a Max of 4 Watts (UHF) or 5 Watts (VHF). Be sure to adjust all seven softpot settings to the desired power level using a RF power meter. The VRS750 determines its Tx Output Power by comparing the programmed frequency to the test frequencies and selecting the softpot value of the one that is closest. Once the softpots have been set to the desired power level click on the program button and close the Transmit Power window by using the X in the top right corner. At this point the mobile radio will reset. After the reset is complete select File->Program All. This will program all adjusted softpot values into theVRS750s EEPROM. Note: We recommend the LOW Transmit Power setting of 300mW for optimal performance. This output power provides the VRS750 with a similar range as the portable when attached to a mobile antenna. Any deviation from this setting could result in a loss of communication from the portable to the base. Figure 13 Transmit High Power window in the Global Tuner To adjust the Receiver Squelch select RX Align->Squelch Attn.->(Select the Squelch Attn. for the channel spacing selected in the VRS Personality) (see Figure 14). The Receiver Squelch should be set at the factory to a tight setting. To obtain better performance from the VRS750 the Squelch softpot setting can be reduced, but if it is reduced too much the VRS750 will enter a monitor state and will not activate. Most settings should be above 30. Once the softpots have been set to achieve the desired squelch level click on the program button and close the Squelch Attn. window by using the X in the top right corner. At this point the mobile radio will reset. After the reset is complete select File->Program All. This will program all adjusted softpots values into the VRS750s EEPROM. Note: We recommend that the Receiver Squelch be adjusted only if the VRS Tx Squelch Type is set to CSQ. Otherwise, the Tx PL Self-Clearing feature may not work properly. Figure 14 Squelch Attenuation Window in the Global Tuner The following table shows the softpot ranges to achieve approximately -110dBm. The actual value varies from radio to radio. The VRS transceiver ships from the factory with the softpot set for -110dBm. In the event that this value needs to be re-set in the field, it is recommended that a communications analyzer or similar piece of test equipment be used to verify these settings. Band Channel Spacing Approximate Softpot Range for -110dBm 56-63 63 44-52 63 43-46 63 25kHz 12.5kHz 25kHz 12.5kHz 25kHz 12.5kHz VHF VHF UHF R1 UHF R1 UHF R2 UHF R2 Other adjustments can be made using the Global Tuner, but it is recommended that all other tuning be performed by a Motorola Service Center. VRS750 Upgrade Kit The VRS750 firmware can be reprogrammed/reflashed using the VRS750 Upgrade Kit. In order to use the VRS750 Upgrade Kit the VRS750 should be connected to a desktop or laptop PC via a COM port as indicated in Figure 12. The Flash adapter (NTN4056A) should be placed between the VRS750 programming cable (3085031D02) and the SRIB. When connecting the VRS750 to the SRIB via the Flash adapter, make sure that the switch on the adapter is in the OFF position. With the ASTRO mobile powered on and PROG VRS displayed on the control head, the upgrade can be started. Open the VRS750 Upgrade Kit and click on the PROGRAM button. Follow the instructions through to the completion of the Flash process. Upon completion, place the switch on the Flash adapter back in the OFF position and disconnect the VRS750 from the programming cable. For more detailed information on the flashing process, consult the read me file for the Upgrade Kit. Note: The VRS750 Upgrade Kit will request which baud rate to use when flashing the first radio. For the VRS750 the baud rate should not exceed 38,400 bps. 5. Detailed VRS Operation Multi-VRS Operation The VRS is designed to accommodate multiple VRS units in the same area. This is accomplished by each VRS maintaining a priority level or delay state. During either portable-to-base or base-to-portable transmissions, only the highest priority VRS will transmit or cause a mobile PTT. The procedures for determining priority levels in multi-

VRS operation are discussed next. Determining Priority Levels Whenever a VRS is enabled, it transmits a Single Tone burst (except if portable activity is already present). The Single Tone burst frequency is fixed at 847.5 Hz. By default, when a VRS (VRS number 1) unit is enabled, it becomes the priority unit with a delay state of zero. When a second VRS unit (VRS number 2) is enabled in the area, it will transmit a Single Tone burst as described. Upon receiving this signal, VRS number 1 will know that another VRS is active and change its priority to delay state one from delay state zero. If a third VRS were to be enabled, VRS number 1 would change to delay state two and VRS number 2 would change to delay state one. This process could continue up until delay state seven is reached by VRS number 1, meaning that eight VRS units have been enabled. After eight VRS units are activated, they begin to stack up at delay state seven. Portable-to-Base Transmissions If a portable begins to transmit, only the highest priority VRS will PTT its corresponding mobile for transmission to the base. The other VRS units, however, will be able to hear the portable transmission and monitor for mobile channel activity. Channel activity is verified by a squelch detect of the mobile. For non-priority units, the portable's audio will be sent to the mobile's speaker (unmuted) from the VRS, not from the mobile. This allows the mobile to monitor the correct transmit frequency. If mode steering options are enabled then the non-priority VRS units monitor their mobile's channel activity on the channel steered to by the portable's PL and not on the mobile's current user selected channel. The non-priority VRS units have a short delay in which they expect to see the squelch detect message. Conventional system units will wait at least 600 ms and trunking system units will wait at least 1500 ms. This time period is referred to as one delay state. If in the appropriate time frame a squelch detect message is not received, the priority VRS unit is assumed to have been disabled and all other VRS units will increase one priority level

(for example, go from delay state 2 to delay state 1). The VRS units will continue to count down until a squelch detect message is received. In an extreme case, in which all but the lowest priority VRS units are disabled, it is possible that the remaining VRS unit which was the lowest priority (highest delay state) will have to wait up to 7 delay states before transmitting. This can lead to a transmission delay of up to 10.5 seconds for a trunking unit. On conventional modes if the VRS <Base Repeater> option is enabled via CPS, then an additional 300 ms time delay is added to the delay states. This allows time for the mobile radios to transmit to and receive from a repeater site. Base-to-Portable Transmissions When a base transmits, only the priority VRS unit will transmit to the portable. The other VRS units monitor activity on the portable channel. Similar to the previous case, if portable activity is not detected in the specified time frame after receiving mobile channel activity, the non-priority VRS units will decrease one delay state, until eventually one unit is in priority. During base-to-portable transmissions, the delay state timing is slightly different from that encountered during portable-to-base transmissions. On conventional modes, the first delay state is 1 second; on trunking modes, the first delay state is 3.4 seconds. All other delay states, on either trunking or conventional modes, are 400 mS. The worst-case delay for a unit to count into priority during a base-to-portable transmission in a trunking system would, therefore, be 5.8 seconds. See the description of the Portable Priority Interrupt feature on page 23 for information on the self-clearing feature used to re-establish a single priority unit when multiple units are mistakenly in priority. This condition may occur when a VRS unit is activated before arriving on a scene, or in the unlikely case where several units stack up at delay state seven and all higher priority units (those in delay states one through six) leave the scene first or are otherwise disabled. Single Unit Operation Normal radio communication between a VRS-equipped vehicle (unit A) and the base is via the mobile radio. When the operator decides to leave the vehicle and use the VRS option, simply press the VRS button or remove the portable from the charger if VIP operation is enabled to turn on the vehicle's repeater. The repeater transmits the Single Tone burst on the associated portable radio frequency and sets the delay state to zero. When the delay state is zero, this unit is the priority unit. See Figure 7. IMPORTANT NOTE:

repeater system. The VRS unit should always be disabled when the vehicle is moving. FAILURE TO DO SO COULD RESULT IN ERRATIC SYSTEM OPERATION. Figure 7 Single VRS Unit Operation Two-Unit Operation The arrival of another VRS-equipped vehicle (unit B) into the coverage area of unit A has no effect on unit A's radio operation until unit B's VRS is enabled. Unless there are portable transmissions occurring when unit B arrives, unit B's repeater transmits a Single Tone burst when its VRS option is turned on. Unit B's repeater priority counter initializes in delay state zero, making unit B the priority unit. Unit A's repeater/portable receives unit B's Single Tone transmission, which sets unit A's repeater to delay state one. See Figure 8. Transmissions from portable units in the area now repeat through unit B. See Figure 9. Figure 8 Two-Unit VRS Operation Figure 9 Two-Unit VRS Transmissions A portable radio's transmissions (solid arrows in Figure 9) go to all portable radios and VRSs in the area. Because unit B is the priority repeater, it repeats the portable's signal

(open arrows in Figure 9) to the base station and other mobile radios. Unit A cannot countdown and repeat until the delay state one time delay elapses. However, because unit A detects the mobile carrier of the priority unit (open arrow in Figure 9) before the delay expires, the priority counter does not begin the countdown. Unit A remains in delay state one and does not repeat portable transmissions. The VRS is designed to be a stationary If unit B activates its VRS during portable transmissions, unit B does NOT transmit Single Tone or enable in delay state zero. Unit B must wait until it cannot detect the portable signal before transmitting Singletone and taking over as the priority unit as described above. Three-Unit Operation Should another VRS-equipped vehicle (unit C) come into the area, the same sequence of events occurs as previously described in the "Two-Unit Operation" section on page 21. Unit C's arrival has no effect on unit A's or B's radio operation until unit C's VRS is enabled. Unless there are portable transmissions occurring when unit C arrives, unit C's repeater transmits a Single Tone burst when its VRS option is turned on. Unit C's repeater priority counter initializes in delay state zero, making unit C the priority unit. Unit A's repeater/portable receives unit C's transmission which sets unit A's repeater to delay state two. Unit B's repeater/portable receives unit C's transmission which sets unit B's repeater to delay state one. Transmissions from portable units in the area now repeat through unit C. All lower-priority units will receive incoming portable transmissions, but will not key up their mobiles because they are in a delay state. See Figure 10. Figure 10 Three VRS Unit Transmission Sequence Departure of a VRS Unit The priority unit may change, depending upon the order in which they leave, as vehicles leave the coverage area. For example, in Figure 10, when unit A turns the VRS option off, it has no effect on the priority unit (unit C). Unit C continues to be the priority unit and repeat transmissions. When the priority unit (unit C) turns the VRS option off and conditions for repeater transmissions occur, the unit in delay state one (unit B in Figure 10) counts down to delay state zero and becomes the priority unit. See Figure 11. IMPORTANT NOTE:

Non-priority units (those in delay state 1 or higher) will not count down into priority if the portable user attempts to send a status or message. If there is no priority unit on scene, the request will be ignored. Figure 11 Priority Unit Reassignment Rptr PPI - Portable Priority Interrupt

<Rptr PPI> is CPS programmable. The main function of <Rptr PPI> is to allow the portable to interrupt base-to-portable transmissions. During VRS to portable transmissions, an interrupt is sent to the transmitter every 2 seconds on conventional modes and 1 second on trunking modes. (These times are CPS programmable and may be changed to 500 ms for trunked modes or 500 ms for conventional modes.) There is also a random time factor added to the base interval to prevent two VRS units from interrupting at the same time. This interrupt allows the receiver to monitor portable or other VRS activity for approximately 6 ms. See the timing chart in Figure 12. Figure 12 Portable Priority Interrupt As an example, consider a case in which both units A and B are in the priority Self-Clearing - This is used when two or more priority VRS units are on the same If a portable's signal without PL tone is present when the repeater is interrupted, the repeater transmitter remains inhibited for the duration of the incoming signal. If the portable's signal is modulated with a PL signal, the priority unit repeats the message back to the base station on top of the incoming signal. In addition to giving the portable user priority over all incoming signals, the Portable Priority Interrupt is used for three basic functions:

1. scene. On the first base-to-portable transmission, all priority VRS units will start to transmit. The first one to have an interrupt and detect carrier without proper portable PL

(meaning another VRS is transmitting) will count up to priority state one, a condition which is referred to as self clearing. This will continue to happen until only one priority VRS is on scene. state (delay state zero). When conditions for repeater transmitting begin (i.e., the mobile receives a base signal), both VRS units begin transmitting. Figure 13 shows the unit B interrupt pulse occurring first (due to the random time factor added to the interrupt interval). When unit B is interrupted, it detects another VRS unit transmitting and so unit B's transmitter remains inhibited. Unit B is set to delay state one and unit A remains the priority unit since by the time unit A's transmitter is interrupted, unit B is no longer transmitting. Figure 13 Self-Clearing Timing Diagram 2. or trunked system during hangtime. The timing is faster for trunked systems due to the added feature of talk permit tones being passed to the portable. If the portable keys up with proper PL, then the VRS will key up the mobile. If proper PL is not sent, the VRS will assume another VRS is in the area and count itself out of priority. NOTE:

transmission trunking enabled, the Quick Key feature becomes useless, since the user will be unable to break-in during the repeater hangtime after the channel is acquired. For this reason, repeater PPI should always be ENABLED on an analog trunking system. 3. transmissions, the signal drops out for approximately 6-8 ms every: 2 seconds

(conventional); or 1 second (trunking) if the "slow" PPI option is chosen; or every 500 ms (either trunking or conventional if the "fast" option is chosen in CPS). manner:

transmit to the base. o o from the portable's transmission and switch to receive mode. o o Portable must transmit with the VRS correct access or steering PL. When the VRS transmitter is interrupted, the VRS will detect channel activity Emergency - This allows the portable to have priority over dispatch. A drawback of portable priority interrupt is that during all base-to-portable The VRS will then transmit VRS TX Audio to the base. The VRS RX Audio is routed to the mobile speaker. Repeater Hangtime - This allows the user to get back into a conventional repeater During a base-to-portable transmission, the portable user wants to interrupt and The repeater PPI function may be used by the portable user in the following If Repeater PPI is disabled on an analog trunking system with TX PL Self-Clearing As part of the multi-unit resolution prioritization algorithm, TX PL Self-Clearing operates by adding the VRS transmit PL to the list of PLs that the VRS monitors. If a VRS transmit PL is detected by a priority VRS (delay state 0), it will indicate that another VRS is transmitting. This feature will cause the original priority VRS to count up to delay state 1, 2, or 3, and allow the transmitting VRS to remain in priority. The delay state is randomized to prevent multiple units from stacking up in delay state 1. In order to prevent ICM transmissions from other VRS units affecting the priority states, the TX PL Self-Clearing feature only works when detecting TX PL from a VRS that is repeating a Base-To-Portable transmission. This function is not programmable, but has no effect unless TX PL is used. This feature will not operate properly unless all VRS units are programmed to transmit with the same frequency PL, and the receiver squelch of the VRS750 units is set to approximately -110dBm. NOTE: The VRS750 ships from the factory with a receiver squelch setting of approximately -110dBm. If the VRS750 is not going to be programmed with a TX PL, then the Global Tuner can be used to loosen the receiver squelch for better radio performance. ICM Functions The in-car-monitor (ICM) allows limited use of the mobile while the VRS is enabled.

<ICM Base> Mode In this mode pressing the mobile's PTT will cause the mobile to transmit on the mode shown on the control head display. The VRS will not transmit the mic audio to the portable. During portable-to-base repeat operations pressing the mobile's PTT will result in the talk prohibit tone sounding momentarily and the mic audio will not be transmitted to the portable. When the mic is on HUB portable transmissions will not be heard at the mobile's speaker. When the mic is off HUB only portable transmissions with the proper PL will unmute the speaker. The following paragraphs detail how the VRS should operate in <ICM Base> mode during different cases. 1. No VRS repeat operations in progress and the mobile user initiates a PTT. The mobile will key up and transmit mic audio to the base. Mic-Hi line audio is not routed to the VRS transmitter. During a portable-to-base repeat operation, the mobile user initiates a mic PTT. A momentary talk prohibit tone will be heard and the mic audio will be 2. 3. disabled. During a base-to-portable repeat operation, the mobile user initiates a mic PTT. The base-to-portable repeat operation will be interrupted. Mic-Hi line audio is not routed to the VRS transmitter. The mobile will key up and transmit mic audio to the base. When the mobile mic PTT is released, the base-to-portable repeat will continue if the mobile is still receiving a base transmission.

<ICM Both> Mode 2. 3. disabled. In this mode pressing the mobile's PTT will cause the mobile to transmit on the mode shown on the control head display and cause the VRS to transmit to the portable. If the portable is using a PL frequency then the VRS can be programmed to transmit the proper PL. During portable-to-base repeat operations pressing the mobile's PTT will result in the talk prohibit tone sounding momentarily and the mic audio will not be transmitted to the portable. When the mic is off HUB all portable transmissions are heard at the mobile's speaker. When the mic is on HUB only portable transmissions with the proper PL will unmute the speaker. The following paragraphs detail how the VRS should operate in

<ICM Both> mode during different cases. 1. No VRS repeat operations in progress and the mobile user initiates a PTT. Mic-Hi line audio is routed to the VRS and transmitted to the portable. The mobile will key up and transmit mic audio to the base. During a portable-to-base repeat operation, the mobile user initiates a mic PTT. A momentary talk prohibit tone will be heard and the mic audio will be During a base-to-portable repeat operation, the mobile user initiates a mic PTT. The base-to-portable repeat will be interrupted. Mic-Hi line audio is routed to the VRS and transmitted to the portable. The mobile will key up and transmit mic audio to the base. When the mobile mic PTT is released, the base-to-portable repeat will continue if the mobile is still receiving a base transmission. If the VRS is in a non-priority state all portable transmissions will be NOTE:

heard on the mobile's speaker. The above descriptions apply to a VRS unit in a priority state. Acknowledgment Tones VRS Mobile-TX Acknowledgment Tones (Conventional Only) When this option is enabled, the VRS transmits a feedback tone after it has received a repeatable message on the portable frequency. This signals the portable operator that the transmission was received. If the repeated message was cut short due to the mobile TOT being exceeded or the mobile channel being changed during the repeat, a lower-pitched tone sounds. If the portable user does not hear a tone after completing a transmission, the portable is either out of range of the repeater or there is no priority repeater in the area. VRS Mobile Trunking Tones (Trunking Only) For trunked modes, the VRS regenerates the standard trunking access tones and transmits them to the portable. These tones, which are essentially the same as those heard at the mobile's speaker, are accessed with the "quick-key" feature. For this operation, the portable user briefly (less than one second) presses the PTT button, and then listens for one of the following tones:

o The "talk permit" tone (three short beeps) indicates to the portable user that the trunking system has granted a voice channel to the mobile and that keying the portable during the trunking system hangtime will result in acquiring this channel. o portable user dekeyed, the trunking system had no voice channel available. If the user The "system busy" tone (a telephone-like busy tone) indicates that, at the time the The "talk prohibit" tone (a long, low tone) indicates to the portable user that the The "trunking access good" tone (a single beep) indicates that a portable-to-base does not key the portable again after receiving a system busy signal, a "talk permit" tone will be transmitted to the portable as soon as a voice channel is available. o mobile cannot access the trunking system. For portable transmissions lasting longer than one second (as opposed to a "quick-key", which must be less than one second), the VRS will respond with one of the following tones. If the "Trunking Access Tones" option is disabled in the "VRS Options" screen of the ASTRO mobile CPS, the "trunking access good tone" and the "trunking access bad tone" will not be generated. o transmission has occurred and the mobile remained keyed for the entire transmission. o The "trunking access bad" tone (a single, low-pitched tone) indicates that all or part of the portable-to-base transmission was not repeated or was interrupted during the portable's valid PL transmission. This would handle, for example, the case of the mobile's TOT expiring or the case where a "system busy" is received first, and then a "talk permit," so that only part of the transmission could be repeated. This tone can also indicate that the VRS has counted down in priority from a delay state of 2 or higher. o mobile cannot access the trunking system. o portable user dekeyed, the trunking system had no voice channel available. If the user does not key the portable again after receiving a system busy signal, a "talk permit" tone will be transmitted to the portable as soon as a voice channel is available. The "system busy" tone (a telephone-like busy tone) indicates that, at the time the The "talk prohibit" tone (a long, low tone) indicates to the portable user that the Message/Status Not Acknowledged Bad Tone-This tone is generated by the Message/Status Acknowledgment Tones There are four different tones that the portable user can receive at the end of a message/status attempt:

o Message/Status Acknowledged Good Tone-This tone is generated by the mobile when the message/status has been acknowledged by the base station. The VRS repeats the tone to the portable. o mobile when the message/status has been transmitted but was not acknowledged by the base station. The VRS repeats the tone to the portable. o Message/Status Not Supported Conventional Bad Tone-This tone is generated by the VRS when it receives a message from the mobile indicating that the message/status number selected is not a valid message or status while the mobile is on a conventional channel. o VRS when it receives a message from the mobile indicating that the message/status number selected is not a valid message or status while the mobile is on a trunking channel. VRS Test Mode VRS can be put into test mode by placing the test mode jumper before system power-up. If the VRS ?P detects this jumper placed during power-up, the following mode is entered:

o Message/Status Not Supported Trunking Bad Tone-This tone is generated by the VRS TEST is displayed momentarily on the control head For the prioritization routine to function, all of the mobiles with a VRS must be Upon reception of a portable frequency RF signal with proper PL, the VRS will Portable Priority Interrupt is disabled VRS TOT disabled TX PL is disabled. It receives a Single Tone burst at the fixed frequency of 847.5 Hz. During a base-to-portable repeat, it receives a VRS/portable frequency RF signal o o o To exit the test mode, the system needs to be reset after removing the test mode jumper. Non-Priority VRS Rules A priority VRS is placed into non-priority mode when one of the following occurs:

1. 2. without proper PL during the PPI. When a VRS goes from priority to non-priority, the internal delay state changes from 0 to 1. Upon subsequent reception of Single Tone bursts (that is, other VRS units activate in the same coverage area), the non-priority unit will increase delay states up to a maximum of 7. While in non-priority, the following occur:

Portable-to-Base Non-Priority Operation 1. determine if the mobile of another VRS system is repeating the signal. 2. able to receive other mobile transmissions, either directly (TX=RX), or on a trunked system (TX?RX), or through a base repeater (TX?RX) in conventional modes with the

<Base Repeater> feature enabled. For conventional non-repeater dispatch systems

(TX?RX), the Mobile Detector must be enabled for the prioritization routine to function properly. 3. portable signal by steering the mobile to the mode corresponding to the received PL. If, within one delay state (at least 600 ms for conventional, at least 900 ms for <Base Repeater>, and at least 1.5 seconds for trunking), the mobile in the non-priority VRS system does not receive the repeated signal, it will countdown from the current delay state. 4. and start repeating. The maximum delay for a non-priority VRS to countdown into priority is 4.2 seconds for conventional, 6.3 seconds for <Base Repeater>, and 10.5 seconds for trunking. 5. will stop the countdown process and stay non-priority. Base-to-Portable Non-Priority Operation 1. a VRS-to-portable transmission from another VRS system (that is, a signal on the portable frequency without proper VRS access PL). 2. countdown from the current delay state. 3. and start repeating. The maximum delay for a non-priority VRS to countdown into priority is 3.4 seconds for conventional and 5.8 seconds for trunking. Upon reception of a repeatable base signal, the non-priority VRS will monitor for Upon reaching delay state 0, the non-priority VRS will become the priority VRS Upon reaching delay state 0, the non-priority VRS will become the priority VRS If the VRS does detect another VRS system repeating within the delay state, it If, within one delay state, the VRS does not receive the repeated signal, it will The VRS will determine if the mobile of another VRS system is repeating the While receiving a portable transmission with correct repeat qualifiers, the unit If the VRS does detect another VRS system repeating within the delay state, it If the VRS detects a portable frequency signal with proper PL while receiving a During a portable-to-base transmission with correct PL, the non-priority VRS will 4. will stop the countdown process and stay non-priority. 5. repeatable base signal, it will handle it according to the portable-to-base case. ICM Non-Priority Operation The ICM feature will continue to operate as described in the "ICM Functions" section except for the following:

1. will not repeat as long as the unit is non-priority. 2. steer the mobile to the mode programmed for that PL frequency. This allows the mobile to monitor for priority repeater traffic. Emergency Emergency Feature Summary An emergency alarm is initiated when the VRS receives a portable transmission which contains the Emergency Alarm PL, as programmed in the mode-steering screen of CPS. Upon decoding the Emergency Alarm PL, the VRS sends an "enter emergency" bus message to the mobile radio. The mobile radio will respond as if the Emer button had been pressed on the control head, and will proceed with the Emergency operation which is programmed by the CPS. In addition, an "emergency acknowledgment" tone is transmitted by the priority VRS as part of the automatic multi-unit priority resolution algorithm. The "Emergency ACK"

tone generated by the VRS is a 1250 Hz tone lasting 500 ms in duration. Once in Emergency Alarm, the VRS ignores subsequent portable transmissions with the Emergency Alarm PL until the mobile exits Emergency. (The "Emergency ACK" tone, however, will always be generated in response to each portable transmission with the proper Emergency Alarm PL). Emergency Call and VRS are mutually exclusive. Even if the mobile is programmed for alarm and call, when the alarm case is exited, the mobile will not transition into Emergency Call while the VRS is activated. Likewise, if the mobile is in Emergency Call, the VRS cannot be activated. Emergency Feature Operation Whether the mobile is programmed for silent or non-silent alarm is transparent to the VRS. However, the Emergency Alarm sequence changes slightly between the silent and non-silent case. The main differences are listed below:

1. Emergency:

o o o o Extended keypress of the Emer button on the mobile's control head. Mobile microphone PTT or a portable-to-base repeat. Mobile exhausts its retries without receiving an "Emergency ACK" from the base. The mobile receives an "Emergency ACK" from the base. The alarm exit sequence For non-silent alarm, any of the following will cause the mobile to exit For silent Alarm, any of the following will cause the mobile to exit Emergency:

Extended keypress of the Emer button on the mobile's control head. o Mobile mic PTT or a portable-to-base repeat. o 2. The mobile will not unmute due to base traffic during silent alarm, and therefore the priority VRS will not attempt a base-to-portable repeat. If there are other, non priority VRS units in the area, they will perform the base-to-portable repeat without counting into priority. IMPORTANT NOTE:

message or status from the portable will be ignored and WILL NOT cause the mobile to exit Emergency. While in Emergency, attempts to send a 6. Hardware Detailed Theory of Operation The VRS750 contains two main modules : an HT750 transceiver and an interface board. I - The HT750 transceiver : This module is an Analog synthesized FM device that contains the receiver, transmitter, and controller section (Refer to manual 68P81088C46-

A). A flex cable connects the HT750s two accessory connectors to a single connector, J30, on the interface board. The HT750s RF jack is connected to W101 on the interface board via the 50 ohm coaxial cable. The VRS750 software is embedded in the HT750 digital portion of the controller which consists of a microcontroller and associated EEPROM, RAM, and ROM memories. II - The interface board: this board provide power regulation, bus translation circuitry, audio routing circuitry, Single Tone Encoder and Decoder circuitry, programming circuitry, and mode configuration. Power Regulation:

The VRS750 is powered by the mobiles Radio_SWB+ (13.8VDC) at the connector P102-22. L101 and C137 are used to filter alternator whine from this signal before providing it as SWB+ to the interface board. The VRS750 utilizes the mobiles analog

(P102-2,11,21) and digital grounds (P102-18). U111 regulates the SWB+ down to +5VDC. This voltage provides power for several switching transistors and voltage dividers on the VRS750 board. U118 is a micropower low dropout regulator used to provide +9.6V for all of the analog audio circuitry. R162 and R164 form a divider network from this 9.6V to produce the 4.8V

(VAG) used to bias the audio circuits. Finally, U129 is a three-terminal regulator used to provide the regulated 7.5V to the HT750 transceiver via Q113 in the reset circuit. SW7.5V is provided to the HT750 at pad P31. Bus Translation Circuitry:

The devices U100-2, U103, Q100, Q101, Q102, Q103, and Q104 are used to separate messages from the bi-directional SB9600 serial bus Bus+, Bus-, and Busy into and from the single direction RXD, TXD, BUSY OUT, and BUSY IN signals at the HT750. The HT750 microcontroller can be reset by an external device by generating an active high reset pulse at pin P102-19, RADIO_RESET. This will cause Q109 to drive J30-5 low. Audio Routing Circuitry:

There are four paths which are used to route audio between the mobile and the HT750 transceiver: AUX_RX_AUD, TX_AUDIO, MOB_MIC_HI and FIL_AUD. During the three types of communications of the VRS (Portable-to-Base, Base-to-Portable, and In-

Car-Monitor), the routing is as follows:

Portable-to-Base:

On channel RF signals are received by the HT750 through the connector, W101. The HT750 provides demodulated audio to the interface board at EXT_SPKR+ (J30-17) and URX_SND (J30-11). The receive audio at EXT_SPKR+ is volume controlled by the HT750. The HT750 monitors the mobiles volume setting and then updates its volume accordingly. The audio is filtered by a 2-pole low pass filter, U107-1, which has a corner frequency of 3.2kHz. T1, a 600-ohm to 600-ohm audio transformer, is used to isolate any ground noise such as alternator whine from the receive audio before being routed to the mobile at AUX_RX_AUD (P102-7). During portable-to-base transmissions the mobile routes this audio to its speaker. The receive audio at URX_SND is at a fixed level of 260mVrms. It is attenuated through op amp circuit U104-3 to a level of 60mVrms which can be adjusted via potentiometer R146. T2, a 600-ohm to 600-ohm audio transformer, is used to isolate this audio from any ground noise such as alternator whine before being routed to the mobile at TX_AUDIO, P102-8. During portable-to-base transmissions, the mobile routes TX_AUDIO to its transmitter. Base to Portable:

The MIC_FIL_SEL (J30-15) and TONES-MOBILE_AUD (J30-8) control signals are generated by the HT750s microcontroller and are used to control audio routing circuits, U101-1 and U101-3, for Base to portable activities. FIL_AUD (P102-6) - This audio path contains receive audio from the mobile during Base-to-portable transmissions. The receive audio passes through op amp circuit U104-1 and can be level adjusted via potentiometer R150. When a base-to-portable repeat occurs, TONES_MOBILE_AUD is in a low state and MIC_FIL_SEL is in a high state so that FIL_AUD is routed to the HT750s transmitter input(EXT_MIC, J30-19). In-Car-Monitor:

The MIC_FIL_SEL (J30-15) and TONES-MOBILE_AUD (J30-8) control signals are generated by the HT750s microcontroller and are used to control audio routing circuits, U101-1 and U101-3, for In-Car-Monitor activities. MOBILE_MIC_HI (P102-12) - This audio path contains microphone audio from the mobile during In-Car-Monitor (ICM) transmissions. The microphone audio passes through op amp circuit U104-4 and can be level adjusted via potentiometer R148. During an ICM transmission, both MIC_FIL_SEL line and TONES-MOBILE_AUD line are set to a Low state to configure both mux U101-3 and mux U101-1 to route the mobile mic audio to the HT750s transmitter input (EXT_MIC, J30-19). Single Tone Encoder :

The VRS750 Single Tone Encoder (U100-1, U124-3, U124-2, and U124-4) is used to produce a tone which is transmitted by the HT750 transceiver when the VRS750 is activated. Other VRS750 repeaters that are on in the operating area receive this Single Tone transmission. The other repeaters will then increment their priority counters by one while the transmitting VRS750 goes to delay state zero and becomes the priority repeater. When the VRS750 is in transmit mode for Single Tone, the HT750 microctonroller generates a square wave at a set frequency of 847.5Hz to the SNGL_TX_DATA (J30-6) pin. The control signal, TONES-MOBILE_AUD, is set to a High state to allow the Single Tone signal to be routed to the input of the Single Tone Filter. The Single Tone Filter is a band pass filter that allows frequencies between 300Hz and 1.7 kHz. U124-4, R126 and R127 are for gain adjustment. The resulting sine wave is then sent to the HT750 transceiver to be transmitted on EXT_MIC (J30-19). This circuit is also used when the HT750 generates various VRS750 acknowledgment tones. Single Tone Decoder:

The VRS750 Single Tone Decoder (U100-1, U124-3, U124-2, and U124-1 detects other Single Tone transmissions, then increments the priority counter. VRS_TX*_RX from the HT750 microprocessor is set to a High state when the VRS750 is in the Single Tone Decode mode (receive mode). When this signal is high, U101-2 allows HT750 receive audio (URX_SND, J30-11) to pass to buffer U100-1. The output of the buffer drives the low-pass filter that is also used in the encoder circuit. U124-1 and the associated diodes, D100 and D101, produce a square wave which is divided down to 3.3V by R172 and R173. This signal, SNGL_DET(J30-12), is then sampled by the HT750 microprocessor to determine if Single Tone is present. Boot Control Circuitry:

The firmware for the VRS750 is stored in the HT750s Flash memory. This firmware can be programmed using the VRS750 Upgrade Tool (refer to section ?). Prior to programming the firmware, the HT750 must be placed into bootstrap mode. To place the HT750 into bootstrap mode, it must be reset while the BOOT-CNTRL (J30-

28) pin is grounded. This pin is grounded when the programming cable is connected and the flash adaptor switch is turned on. Refer to Figure ?. When the BOOT-CNTRL line is grounded, Q100 which controls U102 and U105, is opened and 9.6V passes through U102-2 to the base of Q112. Q113 opens and disconnects SW7.5V from 7.5V. At this point there is no supply voltage to the HT750. Meanwhile, 9.6V is also applied to the base of Q112 thus charging up capacitor C182. After approximately 1.5 seconds, C182 is charged to a voltage that saturates Q111, causing Q112 to open and Q113 to turn On. SW7.5V is connected back to 7.5V again. At this point the HT750 has been reset and is now in bootstrap mode. To prevent mobile bus messages from corrupting the flash programming of the HT750, the control signals to U102-3, U105-2 and U105-3 are applied with 9.6V to disconnect the Bus+ (P102-5), Bus- (P102-14) and Busy (P102-23)lines from the mobile when the BOOT-CNTRL line is grounded. Program Sense:

The PROG_SENSE signal(J30-10) is monitored by the VRS to detect when the programming cable is connected at connector P101. This line will be pulled to ground when the programming cable is connected or will be 3.3VDC when the programming cable is not connected. The programming cable is used when adjusting the VRS using the Tuning Tool (refer to section ?) or when updating the VRS firmware using the VRS750 Upgrade Tool (refer to section ?). Mode Configuration:

There are various operating modes of the VRS750. The mode is selected at power-up based on the settings of dipswitch S1 pins 1, 2 and 3. Pin 4 is unused. The following table shows the supported modes:

Operating Mode Normal Test Mode ATE Test Mode HT750 CPS Mode Normal mode is the default and standard configuration for the VRS750. Test Mode and ATE Test Modes are used by Motorola for testing purposes. HT750 CPS Mode is available for when the user requires the transmit and receive frequencies to differ. Operation during this mode is not advised and if required please contact your Motorola S1 Pin 1 On Off On Off S1 Pin 2 On Off Off On S1 Pin 3 On Off Off On sales representative for details about this mode. All other combinations of the dipswitch are not supported and will default to the Normal mode. 7. Maintenance and Troubleshooting ERR 12/81 - Flash EPROM failure. If re-flashing the unit does not fix this Turn on the mobile radio control head. The radio should go through self-check ERR 12/82 - Codeplug checksum error. After verifying that both mobile and VRS Possible error messages on power up are:

ERR 12/10 - No VRS detected. See "Common Power Up Problems" section on The following paragraphs contain information to help you maintain and troubleshoot the VRS. A list of recommended test equipment is found in the "Recommended Test Equipment, Service Aids, and Tools" section of the ASTRO Spectra Basic Service Manual, Motorola publication 68P81076C20. Additional information may be found in the Troubleshooting Chart in this manual. Troubleshooting Procedures VRS Activation 1. and then display the home mode of the mobile radio. 2. o page 38 for possible solutions. o problem the HT750 transceiver should be replaced. o have the correct software version, checking the mobile-to-VRS connection, and moving the cable away from any interference, reprogram the VRS750's codeplug using the correct version of the CPS. If the codeplug cannot be corrected using CPS then the unit will need to have a new default codeplug written to the unit. o correct version software. If this fails to correct the problem, the HT750 transceiver should be replaced. o o Problems" section on page 38 for possible solutions. If the solutions in the Common Power Up Problems section do not fix the error then the HT750 transceiver should be replaced. o PROG VRS - The VRS750 is in programming configuration. This is only an error if the programming cable is not plugged into the front connector of the VRS750. Reset the ASTRO Mobile radio and if the problem is not corrected check P101 Pin 9 and the PROG_SENSE line for any shorts to ground. 3. o indicator must light. o KHz deviation for a channel spacing of 25 kHz. NOTE: Because of the short burst, it may be necessary to verify the deviation on the modulation scope instead of the usual deviation meter. Activation may be repeated by pressing the VRS button once to disable the unit and again to reactivate it. Enable the VRS unit by pressing the VRS button on the mobile control head.

"VRS BOTH" must be displayed momentarily on the control head and the ERR 12/88 - HC11 RAM failure. Replace the HT750 Transceiver. VRS 001 - VRS Synthesizer out of lock error. See "Common Power Up Verify a short single tone burst is transmitted upon activation at approximately 3 ERR 12/84 - CONFIG register corruption. The unit should be flashed with the Check the VRS750's squelch setting. Check all regulators for proper voltages. The 9.6-volt regulator is accessible at

"VRS BOTH" message does not display momentarily on control head when VRS VRS is receiving a VRS frequency signal. (VRS will not display "VRS BOTH" or Check the VRS750's codeplug for incorrect programming. Re-flash the VRS750 with new firmware using the VRS750 Upgrade Tool.

"VRS 001" message is displayed on power-up. VRS Frequency Band in the VRS Personality of the ASTRO Mobile codeplug is

"ERR 12/10" message is displayed on power-up. The VRS mobile interface cable is disconnected or bad. Verify the VRS Firmware is correct. Immediately after power up press the HOME Common Power-Up Problems 1. o o button on the control head five (5) times and verify the correct firmware version is displayed. o C199. Do not probe U118 pin1 when the unit is powered. U118 will shut down without any recovery if pins 1 and 2 are accidentally shorted to each other. 2. is enabled. o transmit Single Tone if there is RF activity on the VRS frequency.) o 3. o incorrect. o o Common Operational Problems 1. o o o 2. o o o o Disassembly and Reassembly To access the VRS main board, perform the following steps using the reference number from the exploded view as a guide to identify the parts specified:

Accessing the Internal components of the VRS. Remove the top cover (X) from the chassis (X) by prying it over the clips in the left and right rear corners of the chassis. Removing and Reinstalling the PC Board Assembly (X) from the Chassis (X). 1. regulator) from the pc board. 2. 3. 4. Common Portable-to-Base Repeat Problems. Check portable for correct transmit frequency and PL. Check portable for low battery. Check VRS internal RF cable for loose connection. Common Base-to-Portable Repeat Problems Check portable for correct receive frequency and PL. Check mobile for correct frequency. Check that portable is set for the bandwidth corresponding to the VRS. Check VRS internal RF cable for loose connection. Remove the retainer for the RF connector (X). Lift the pc board (X) out of the chassis (X). Remove the eight machine screws (X) (includes the screw used for the voltage To reassemble the pc board and the chassis, reverse the preceding steps. Remove the Flex retainer bracket (X). To reinstall the HT750 transceiver, reverse the preceding steps. Loosen the 4 screws (X) that hold the HT750 retaining rails (X) to the pc board. Slide the HT750 retaining rails apart so that the HT750 transceiver can be lifted Removing and Reinstalling the HT750 Transceiver 1. Remove the nuts and washers holding on the Flex retainer bracket (X). 2. 3. Unplug both the HT750 flex cable (X) from the 20 and 40 pin latch connectors and the VRS coax cable (X), from the pc board (X). 4. 5. away from the pc board. 6. VRS Transceiver (HT750) VRS units use a Motorola HT750 synthesized radio. The HT750 transceiver contains VRS software and can no longer be used as a stand-alone portable. The transceiver does retain its HT750 model number and HT750 serial number internally. No hardware modifications have been made to this radio for use in the VRS. Consult the Professional Radio Basic and Detailed Service Manuals for more information on circuit board layout and tuning procedures. HT750 Transceiver Alignment for VRS The HT750 alignment for the VRS is identical to that shown in the HT750 Instruction Manual, with the exception of the power output and squelch setting. For all VRS models, the HT750 RF output power is adjusted so that the VRS transmits 275 mW for low power and 2 W for high power. The squelch settings for all VRS models are adjusted to closely match that of older crystallized VRS models. The software inside the transceiver is unique to the VRS application. The I/O between the HT750 microprocessor and the VRS 750 controller card is unique. Field repair of the transceiver is not recommended. Contact your local service representative for a replacement transceiver. VRS Tuning and Alignment The VRS is tuned at the factory and should not need to be realigned. Refer to the proper manuals for programming and alignment for the associated radio and control unit before attempting to troubleshoot the VRS unit. If proper tuning of the associated radio fails to correct a problem, the following procedure may be used to align the VRS. Setup ASTRO Spectra Station Cable Setup Ensure that the ASTRO Spectra B+ cable is disconnected from the power supply and the control head is off (WARNING: Never turn B+ power off with the control head still on). Connect the VRS DB-25 cable (HKN6153A) into the accessory connector of the mobile. Connect the other end of the VRS cable to the VRS. Set the test station power supply to 13.8 Vdc and current limiter to 12 amps. Connect the mobile's B+ cable to the power supply. See Figure 14. Figure 14 General Cabling Diagram Figure 15 illustrates the relative placement of the tuning potentiometers. Adjust the VRS Deviation Level:

Set the Mobile Communications Analyzer RF output to -50 dBm, with a standard Switch off the Mobile Communications Analyzer RF. Adjust the Mobile Microphone Deviation Level:

This adjustment requires specialized equipment. If a problem is found with the Set the Mobile Communications Analyzer frequency to the current mobile mode. Switch on the Mobile Communications Analyzer RF. Adjust R150 on the VRS board until 3.0 kHz deviation is obtained on the VRS Tuning Procedure Board-Level Tuning Procedure 1. Place the VRS in the test mode:

Turn off the mobile radio control head. a. Place the VRS into Test Mode by setting dipswitch S1 pins 1, 2, 3, and 4 to OFF. b. Turn on the mobile control head and re-enable the VRS. c. d. While in Test Mode, the VRS will not have portable priority interrupt and will not transmit PL with VRS-to-portable transmissions. f. Figure 15 Tuning Potentiometers 2. a. test modulation (1 kHz tone, 3 kHz deviation). b. c. d. Communications Analyzer. e. 3. o audio transmitted to the portable while using the mobile microphone, Motorola engineering should be contacted. 4. NOTE:

standard test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the VRS is programmed (750 Hz deviation). If the receive PL for "select mode" is not used, the Mobile Communications Analyzer frequency may need to be adjusted. a. b. c. Communications Analyzer. Switch off the VRS Communications Analyzer RF. d. Check the VRS RF Sensitivity:

5. a. Set the VRS Communications Analyzer RF output to -115 dBm with a standard test modulation (1 kHz tone, 3 kHz deviation) and any receive PL for which the VRS is programmed (750 Hz deviation). NOTE:

Communications Analyzer frequency may need to be adjusted. b. this signal to the Mobile Communications Analyzer. c. Communications Analyzer at no more than -104 dBm. d. 6. a. Set the Mobile Communications Analyzer frequency to the current mobile mode. Switch on the VRS Communications Analyzer RF. Adjust R146 on the VRS board until 3.00 kHz deviation is obtained on the Mobile Switch off the VRS Communications Analyzer RF. Take the VRS out of test mode:

Turn off mobile control head and set the dipswitch S1 pins 1, 2, 3, and 4 to ON. Switch on the VRS Communications Analyzer RF. The unit should not retransmit Slowly increase the input signal. The unit should begin repeating to the Mobile Set the VRS Communications Analyzer RF output to -50 dBm with a If the receive PL for "select mode" is not used, the Mobile Adjust the Mobile Deviation Level:

Turn on the mobile control head and re-enable the VRS. Tuning is complete. b. 7. 8. Troubleshooting Charts Introduction to this Section This section contains detailed troubleshooting flowcharts. These charts should be used as a guide in determining problem areas. They are not a substitute for knowledge of circuit operation and astute troubleshooting techniques. It is advisable to refer to the related circuit descriptions in the "Hardware Detailed Theory of Operation" section prior to troubleshooting. List of Troubleshooting Charts Chart Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Description VRS Enable Failure Error 12/10 Error 12/81 Error 12/82, Codeplug Checksum Error Error 12/84, Configuration Register Corruption Error 12/88, HC11 RAM Failure VRS 001, VRS Synthesizer lock error Single Tone Encode Failure Single Tone Failure Base-to-Portable Repeat Failure Portable-to-Base Repeat Failure VRS ICM Audio Failure Serial Bus Failure Portable Audio at Local Speaker Issue Programming/Tuning Failure Page Number 44 45 45 45 46 46 46 46 46 47 48 49 51 51 52 9. Diagrams and Parts Lists Introduction to this Section This section contains schematics, a component layout diagram, an exploded view, and electrical and exploded view parts lists. List of Diagrams and Parts Lists Description Printed Circuit Board Electrical Parts List Printed Circuit Board Component Location Diagram Printed Circuit Board Schematic Diagram Page Number 54-55 56 57-58 59 Exploded View and Exploded View Parts List Chart 15 - Programming/Tuning Failure Chart 5 - Error 12/84, Configuration Register Corruption Chart 6 - Error 12/88, HC11 RAM Failure Chart 7 - VRS 001, VRS Synthesizer Lock Failure Chart 8 - Single Tone Encode Failure Chart 9 - Single Tone Failure Chart 2 - Error 12/10 Chart 3 - Error 12/81 Chart 4 - Error 12/82, Codeplug Checksum Error Chart 10 - Base-to-Portable Repeat Failure Chart 11 - Portable-to-Base Repeat Failure Chart 13 - Serial Bus Failure Chart 14 - Porable Audio at Local Speaker Issue Chart 9 - Base-to-Portable Repeat Failure Chart 12 - VRS ICM Audio Failure Chart 1 - VRS Enable Failure ASTRO Spectra Vehicular Repeater System Model 750 Printed Circuit Board Electrical Parts List (PLN7780A) CAPACITOR, Fixed; pF: unless otherwise stated Reference Designator Motorola Part Number C100,C102,C107,C109,C111,C112,C122,C123,C12 4,C125,C126,C127,C128,C129,C130,C131,C136,C1 38,C139,C142,C146,C147,C150,C152,C154,C157,C 158,C159,C160,C161,C164,C165,C166,C167,C170, C172,C173,C175,C179,C184,C188,C191,C195,C19 7,C199,C201,C202,C203,C204,C205,C206 C101 C103,C104,C132,C133,C148,C183,C189 C105,C108,C120,C143 C113 C114,C115,C116,C141 C117 C118,C145,C180,C194 C119,C185 C121 2113740f59 2113740f39 2311049a08 2113741b69 2113741f33 2113741a45 2113741a49 2113740a79 2113743b21 2113740b49 Description CAP,220pF CAP,33pF cap_polar,1uF CAP,0.1uF CAP,2200pF CAP,.01uF CAP,.015uF CAP,1000pF CAP,0.22uF CAP,100pF C134,C135,C140,C168,C171,C196,C198,C200 2113743e20 CAP,0.1uF C137 C149,C151,C153,C155,C182 C156,C162 C190 D100,D101 J30 L101 P101 P102 Q100,Q101,Q103,Q106,Q109,Q110,Q111,Q112,Q1 14 Q102,Q104 Q113 R101,R108,R172 2380090M40 2311049a19 2380090m25 2113741f21 4805129m05 0985173d01 2505462s03 0905904V02 2805429W03 4880141l02 4813824A17 4813821a21 0662057a93 R102,R120,R121,R124,R127,R136,R137,R155,R16 2,R163,R164,R175,R183,R211,R212,R225 R104,R105 0662057a73 0662057a25 R106,R117,R118,R132,R133,R138,R140,R141,R14 3,R147,R166,R180,R181,R184,R200,R213 R107,R119 R109,R112,R113,R151,R173,R224 R110,R126,R157,R160 R111,R122,R123,R215 R114 R115 R116 R125,R149 R128,R131 R129,R174 R130 R139,R142,R156,R182,R210,R217 R145 R146,R148,R150 R158 R159 R161 R165 R171 R172, R173 R216 R220,R221 0662057a65 0662057a69 0662057a97 0662057a77 0662057a83 0662057b10 0662057a94 0662057a84 0662057a91 0662057p95 0662057p27 0662057p22 0662057a49 0662057a89 1813905a11 0662057a38 0662057a55 0662057a47 0662057a56 0662057t64 0662057a73 0662057b26 0662057a81 cap_polar,2200uF cap_polar,10uF cap_polar,100uF CAP,680pF diode13 connector,30 pin flex inductor,1000uH CONN_J CONN_P NPN PNP nchan_tmosfet_gsd RES,68K RES,10K RES,100 RES,4.7K RES,6.8K RES,100K RES,15K RES,27K RES,330K RES,75K RES,30K RES,56K RES, 100K 1%

RES, 27.4K 1%

RES, 22.1K 1%

RES,1K RES,47K pot,20K RES,360 RES,1.8K RES,820 RES,2K RES, 47.5K 1%

RES,10K RES,1.5MEG RES,22K S1 T1,T2 U100,U107 U101,U102,U105 U103 U104,U124 U111 U118 U129 VR103,VR104,VR105,VR106,VR107,VR108,VR10 9,VR113,VR121,VR112,VR118,VR102 VR110,VR115 W101 W102 ASTRO Spectra Vehicular Repeater System Model 750 Printed Circuit Board Electrical Parts List 4080564c02 2584422t02 5113818a03 5184704m60 5113806a37 5113819a04 5113816a03 5105109z13 5105469E18 4805129m35 4813830a28 0984345R02 0905901V10 8485176D01 o200835638 o300114832 switch_dip xfmr_6pin mc33072-1 mc14053b mc14106 mc3303 MC78L05A LT1129 LM317T zener13,5.6V zener13,15V Conn SMB Jack Rt. Ang PCB CONN_J pc board nut screw