Microwave Data Systems MDS 4310 Operation Manual

About This Manual

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For information on MDS products, technical support and publication updates, connect to our Internet Web site at http://www.microwavedata.com/. Click on the address to launch your browser.

175 Science Parkway, Rochester, N.Y. 14620, U.S.A. Sales & Customer Support: +1 (716) 242-9600 FAX–All Services: +1 (716) 242-9620 World Wide Web: http://www.microwa vedata.com/

MDS 4310

350–512 MHZ

RADIO TRANSCEIVER

INTERFACE

TR MR CD

TD IN RD

13.8 VDC

ANTENNA

–

Installation, Operation & Field Maintenance

Covering the MDS 4310 Transceiver with the 05-2314Axx PCB,

the MDS 4350 & 4355 Packaged Systems and All Basic Options

MDS 05-2415A01, Rev. A

SEPTEMBER 1994

A CALIFORNIA MICROWAVE DIVISION

MDS 4310 QUICK START GUIDE

Below are the basic steps for installing the MDS 4310 (350—512 MHz) Data Transceiver. The information in parentheses indicates the chapters in this manual where detailed explanations are found.

1. Verify radio set-up parameters. (Chapters 2 & 3)

Check the test data sheets packed with the transceiver to be sure the radio is properly configured for the intended application. Check especially for these items:

• Proper configuration of software selectable settings such as, CTS delay, soft carrier dekey (SCD), squelch tail eliminator (STE), time-out timer (TOT) and PTT delay. Chapter 3 gives instructions for setting these parameters.

• Transmit and Receive frequencies.

(Should be the same as those listed on the station license.)

• Transmitter RF power output.

• Loopback Code.

(Default loopback code consists of the last four digits of the radio’s serial number.)

• Transmit modulation and audio input characteristics.

• Modem speed (if radio is modem-equipped).

2. Securely mount the transceiver. (Chapter 2)

• Use the MDS supplied mounting brackets and four screws or bolts (fasteners not provided).

• Choose a mounting location that allows easy access to the connectors on the end of the radio and allows an unobstructed view of the LED status indicators.

3. Install and connect the antenna system to the radio. (Chapter 2)

• Use good quality, low loss coaxial cable.

• Keep the antenna feedline as short as possible.

• Avoid sharp bends in the coaxial cable.

• Preset the antenna in the direction of the master station.

• Properly waterproof the antenna connector.

4. Connect and apply DC power to the radio. (Chapter 2)

• Set supply voltage to a nominal 13.8 volts.

• Observe polarity.

• Power cord must be properly fused (3 Amperes).

• Plug in the power plug and tighten the retaining screw.

5. Verify radio communications by observing the LED display. (Chapter 2)

• See Tables 2-2 and 2-3 for interpretation of status LEDs.

• Refine the antenna heading by using a DC voltmeter or Hand-Held Terminal (HHT) to measure the radio’s received signal (RSSI).

6. Connect the data equipment to the radio INTERFACE connector. (Chapter 2)

• Connection must be made with a DB-25 Male (25 pin) connector.

• Connect only the required pins. Do not use a straight-through RS-232 cable with all pins wired.

• Verify the equipment connected to the INTERFACE connector is configured as DTE. The radio is configured as DCE (data communications equipment).

• Pin connections for the INTERFACE connector are summarized in Table 2-1.

MDS 2415A01, Rev. A Front Cover-B

MDS P/N 05-2515A01, Rev. A

SEPTEMBER 1994

MDS 4310

350–512 MHz RADIO TRANSCEIVER

Including the…

MDS 4350 and MDS 4355 PACKAGE MODEL RADIOS

INSTALLATION, OPERATION

AND

FIELD MAINTENANCE

Microwave Data Systems

MICROWAVE DATA SYSTEMS

175 Science Parkway, Rochester, New York 14620 Telephone No.: 716-242-9600, FAX No.: 716-242-9620

The following are trademarks…

Thruline™—Bird, Inc.

HELIAX™—Andrew Corporation.

PCTALK™—The Headlands Press, Inc.

PCPLUS™—DataStorm Technologies, Inc.

PROCOMM™—DataStorm Technologies, Inc.

If further assistance with this product is required, please contact:

MICROWAVE DATA SYSTEMS

A Division of California Microwave Incorporated

175 Science Parkway

Rochester, New York 14620

Telephone No.: 716-242-9600

FAX No.: 716-242-9620

TABLE OF CONTENTS

CHAPTER 1—GENERAL

INTRODUCTION ------------------------------------------------------------------------------------------------------ 1-1 APPLICATIONS-------------------------------------------------------------------------------------------------------- 1-1 TERMS “ANALOG” AND “DIGITAL” ---------------------------------------------------------------------------- 1-2 MDS 4310 MODULATION TECHNIQUES ----------------------------------------------------------------------- 1-2 MICROCONTROLLER FEATURES ------------------------------------------------------------------------------- 1-2 SOFT CARIER DEKEY ----------------------------------------------------------------------------------------------- 1-3 CONTROL INPUTS AND OUTPUTS ------------------------------------------------------------------------------ 1-3

MODEL NUMBER CODES -------------------------------------------------------------------------- 1-4

MAIN PRINTED CIRCUIT BOARD MODELS -------------------------------------------------- 1-4 SPECIFICATIONS ----------------------------------------------------------------------------------------------------- 1-5 OPTIONAL EQUIPMENT, ACCESSORIES and CERTIFICATIONS -------------------------------------- 1-10

Special Certifications--------------------------------------------------------------------------------- 1-10

1200 BPS Bell 202T Modem------------------------------------------------------------------------ 1-11

4800 BPS Modem------------------------------------------------------------------------------------- 1-11

9600 BPS Modem------------------------------------------------------------------------------------- 1-11

Audio Processing Module---------------------------------------------------------------------------- 1-11

Order Wire Module----------------------------------------------------------------------------------- 1-11

Remote Maintenance Module (Internal)—P/N 03-1958A01 ----------------------------------- 1-11

Hand-Held Terminal---------------------------------------------------------------------------------- 1-12

RS-232 to RS-422 Converter Assembly—P/N 01-2358A01------------------------------------ 1-12

TTL to RS-232 Converter Assembly--------------------------------------------------------------- 1-12

CHAPTER 2—INSTALLATION

OVERVIEW ------------------------------------------------------------------------------------------------------------- 2-1 SURFACE MOUNTING ---------------------------------------------------------------------------------------------- 2-2 EXTERNAL CONNECTIONS --------------------------------------------------------------------------------------- 2-4

ANTENNA Connector --------------------------------------------------------------------------------- 2-4

DC IN (Power) Connector ----------------------------------------------------------------------------- 2-4

INTERFACE Connector ------------------------------------------------------------------------------- 2-4

INTERFACE Connector Pin Functional Descriptions--------------------------------------------- 2-7 FRONT PANEL INDICATORS------------------------------------------------------------------------------------ 2-11 TRANSCEIVER CONFIGURATION JUMPERS --------------------------------------------------------------- 2-12

J14—Receiver Audio Output Phase ---------------------------------------------------------------- 2-13

J16—Full Duplex Option Connector--------------------------------------------------------------- 2-13 MODEMS—GENERAL--------------------------------------------------------------------------------------------- 2-13

Introduction-------------------------------------------------------------------------------------------- 2-13

The Role of the Modem ------------------------------------------------------------------------------ 2-14

RTS and CTS Signals ------------------------------------------------------------------------------- 2-14

DCD Signal -------------------------------------------------------------------------------------------- 2-14 POWER REQUIREMENTS----------------------------------------------------------------------------------------- 2-14 ANTENNAS AND FEEDLINES----------------------------------------------------------------------------------- 2-15

Antenna Selection and Mounting ------------------------------------------------------------------- 2-15

Feedline Selection------------------------------------------------------------------------------------- 2-16

Feedline Installation ---------------------------------------------------------------------------------- 2-17

MDS 2141A01, Rev. A i

CHAPTER 3—PROGRAMMING AND DIAGNOSTICS

INTRODUCTION------------------------------------------------------------------------------------------------------ 3-1 TERMINAL CONNECTION AND STARTUP ------------------------------------------------------------------- 3-1

Opening The Diagnostic Channel -------------------------------------------------------------------- 3-3

CAPABILITIES OF THE HHT -------------------------------------------------------------------------------------- 3-4

Review Operating Parameters and Diagnostic Information -------------------------------------- 3-4 Setting the Operating Parameters--------------------------------------------------------------------- 3-5 Program User Information ---------------------------------------------------------------------------- 3-5

USING THE HAND-HELD TERMINAL -------------------------------------------------------------------------- 3-5

Command Syntax--------------------------------------------------------------------------------------- 3-5 Shift Key------------------------------------------------------------------------------------------------- 3-5 Backspace (BKSP) Key ------------------------------------------------------------------------------- 3-5 Error Messages------------------------------------------------------------------------------------------ 3-6

Closing the Diagnostic Channel---------------------------------------------------------------------- 3-6 PROGRAMMING EXAMPLES------------------------------------------------------------------------------------- 3-6 PROGRAMMING OWNER’S INFORMATION ----------------------------------------------------------------- 3-8 PASSWORD PROTECTION----------------------------------------------------------------------------------------- 3-8 DIAGNOSTIC EVALUATION-------------------------------------------------------------------------------------- 3-8

Test Modes ---------------------------------------------------------------------------------------------- 3-9 EQUIPMENT DIAGNOSTICS DEFINITIONS------------------------------------------------------------------- 3-9 DIAGNOSTIC EXAMPLES----------------------------------------------------------------------------------------- 3-10

RF Power Output Check ----------------------------------------------------------------------------- 3-10

Received Signal Strength Indication (RSSI) Check ---------------------------------------------- 3-10 PROGRAMMING AND TEST COMMANDS ------------------------------------------------------------------- 3-11 HAND-HELD TERMINAL SETUP DEFAULTS --------------------------------------------------------------- 3-13 HAND-HELD TERMINAL WIRING ----------------------------------------------------------------------------- 3-14

Adapter Plug Wiring ---------------------------------------------------------------------------------- 3-14 HHT ALTERNATIVES ---------------------------------------------------------------------------------------------- 3-15

Cable Wiring for a PC or ASCII Terminal -------------------------------------------------------- 3-15

CHAPTER 4—FIELD TESTS AND ADJUSTMENTS

GENERAL -------------------------------------------------------------------------------------------------------------- 4-1 TEST EQUIPMENT REQUIRED ----------------------------------------------------------------------------------- 4-1 CONSTRUCTING A DATA TERMINAL EMULATOR-------------------------------------------------------- 4-3 REMOTE MAINTENANCE CONSIDERATIONS--------------------------------------------------------------- 4-5 INTRODUCTION TO FIELD TESTS & ADJUSTMENTS ----------------------------------------------------- 4-6 TEST PROCEDURES:

Basic Transceiver Checks ----------------------------------------------------------------------------- 4-7

Transmit Frequency, Squelch, Deviation and Receive Audio Output

For Radios with No Internal Modem----------------------------------------------------- 4-10 For Radios with MDS’s Internal 1200 BPS Modem----------------------------------- 4-11 For Radios with MDS’s Internal 4800 BPS Modem----------------------------------- 4-14 For Units with MDS’s Internal 9600 BPS Modem ------------------------------------ 4-16

REMOTE MAINTENANCE MODULE—

Loopback Code Programming, Mode Selection, Calibration & Testing ---------------------- 4-19

ii TABLE OF CONTENTS MDS 2141A01, Rev. A

CHAPTER 5—THEORY OF OPERATION

RECEIVE FRONT END----------------------------------------------------------------------------------------------- 5-1 HIGH IF ------------------------------------------------------------------------------------------------------------------ 5-1 LOW IF ------------------------------------------------------------------------------------------------------------------- 5-1 RECEIVE AUDIO ------------------------------------------------------------------------------------------------------ 5-1 SQUELCH --------------------------------------------------------------------------------------------------------------- 5-2 POWER SUPPLY------------------------------------------------------------------------------------------------------- 5-2 TRANSMIT POWER AMPLIFIER---------------------------------------------------------------------------------- 5-3 ANTENNA SWITCH -------------------------------------------------------------------------------------------------- 5-3 DIRECTIONAL COUPLER------------------------------------------------------------------------------------------- 5-3 KEYLINE AND CONTROL CIRCUITS --------------------------------------------------------------------------- 5-3 RADIO DISABLE ------------------------------------------------------------------------------------------------------ 5-3 AUDIO/DATA MODULATION INPUT SWITCHING---------------------------------------------------------- 5-4 MICROCONTROLLER/EEPROM ---------------------------------------------------------------------------------- 5-4 DIAGNOSTICS DATA CONTROL --------------------------------------------------------------------------------- 5-4 TRANSMIT AUDIO --------------------------------------------------------------------------------------------------- 5-5 PLL/SYNTHESIZER--------------------------------------------------------------------------------------------------- 5-5 RS-232 DATA INTERFACE------------------------------------------------------------------------------------------ 5-5 LED INDICATORS ---------------------------------------------------------------------------------------------------- 5-5

CHAPTER 6—TROUBLESHOOTING

This section contains basic field troubleshooting assistance for the transceiver system.

APPENDIX A—1200 BPS BELL 202T COMPATIBLE MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- A-1 SPECIFICATIONS ---------------------------------------------------------------------------------------------------- A-1 ALIGNMENT ---------------------------------------------------------------------------------------------------------- A-1 THEORY OF OPERATION------------------------------------------------------------------------------------------ A-2

APPENDIX B—4800 BPS FSK MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- B-1 SPECIFICATIONS ---------------------------------------------------------------------------------------------------- B-1 INSTALLATION ------------------------------------------------------------------------------------------------------ B-1 ALIGNMENT ---------------------------------------------------------------------------------------------------------- B-1 THEORY OF OPERATION------------------------------------------------------------------------------------------ B-1

APPENDIX C—9600 BPS FSK MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- C-1 SPECIFICATIONS ---------------------------------------------------------------------------------------------------- C-1 INSTALLATION ------------------------------------------------------------------------------------------------------ C-1 ALIGNMENT ---------------------------------------------------------------------------------------------------------- C-1 THEORY OF OPERATION------------------------------------------------------------------------------------------ C-1

MDS 2141A01, Rev. A TABLE OF CONTENTS iii

APPENDIX D—REMOTE MAINTENANCE MODULE

INTRODUCTION----------------------------------------------------------------------------------------------------- D-1 OPERATION ---------------------------------------------------------------------------------------------------------- D-1 MODULE ADJUSTMENTS & CALIBRATION ---------------------------------------------------------------- D-2 DETERMINING THE PRESENCE OF A REMOTE MAINTENANCE MODULE ----------------------- D-2 INSTALLATION & REPLACEMENT---------------------------------------------------------------------------- D-3 TESTING THE LOOPBACK CODE ------------------------------------------------------------------------------ D-4 TROUBLESHOOTING ---------------------------------------------------------------------------------------------- D-4 THEORY OF OPERATION ----------------------------------------------------------------------------------------- D-5

APPENDIX E—ORDER WIRE MODULE

INTRODUCTION------------------------------------------------------------------------------------------------------ E-1 THEORY OF OPERATION ------------------------------------------------------------------------------------------ E-2

APPENDIX F—MDS 4355 REMOTE RADIO PACKAGED SYSTEM

GENERAL INFORMATION----------------------------------------------------------------------------------------- F-1 INTERFACE ASSEMBLIES----------------------------------------------------------------------------------------- F-2

Analog Interface Assembly—P/N 03-1105A21 --------------------------------------------------- F-2

RS-232/TTL Digital Interface Assembly—P/N 03-1467A21 ------------------------------------ F-2 POWER CONNECTIONS -------------------------------------------------------------------------------------------- F-3

Primary Power—J3------------------------------------------------------------------------------------- F-3

Power for Accessories --------------------------------------------------------------------------------- F-3

Back-up Battery ---------------------------------------------------------------------------------------- F-3 ANALOG INTERFACE BOARD CONNECTIONS—P/N 03-1105A21, Rev. C---------------------------- F-4

Audio and Keyline—J1-------------------------------------------------------------------------------- F-4

Additional Interface Connections -------------------------------------------------------------------- F-4

Audio Alignment --------------------------------------------------------------------------------------- F-5 DIGITAL RS-232/TTL INTERFACE BOARD CONNECTIONS, P/N 03-1467A21 --------------------- F-11

Summary----------------------------------------------------------------------------------------------- F-11

RS-232 Digital Interface Connections------------------------------------------------------------- F-12

TTL Digital Interface Connections ---------------------------------------------------------------- F-12

Additional Interface Connections ------------------------------------------------------------------ F-12

Order Wire Audio Alignment ---------------------------------------------------------------------- F-12

APPENDIX G—MDS 4355 REMOTE RADIO PACKAGED SYSTEM

GENERAL INFORMATION---------------------------------------------------------------------------------------- G-1 CUSTOMER MODIFICATION ------------------------------------------------------------------------------------ G-2 MOUNTING ----------------------------------------------------------------------------------------------------------- G-2 INTERFACE ASSEMBLIES—Summary ------------------------------------------------------------------------- G-5

Analog Interface/Utility Assembly—P/N 03-2110A01------------------------------------------ G-5

RS-232 Digital Interface and Utility Board—P/N 03-2115A01 -------------------------------- G-5 USING THE MDS HAND-HELD TERMINAL------------------------------------------------------------------ G-5 POWER CONNECTIONS ------------------------------------------------------------------------------------------- G-6

Primary Power—TB2--------------------------------------------------------------------------------- G-6

Power for Accessories -------------------------------------------------------------------------------- G-7

Back-up Battery --------------------------------------------------------------------------------------- G-7

iv TABLE OF CONTENTS MDS 2141A01, Rev. A

ANALOG INTERFACE/UTILITY BOARD CONNECTIONS—P/N 03-2110A01------------------------- G-8

Audio and Keyline—TB1----------------------------------------------------------------------------- G-8 Additional Interface Connections-------------------------------------------------------------------- G-8 Audio Alignment--------------------------------------------------------------------------------------- G-9 Order Wire Audio Alignment ------------------------------------------------------------------------ G-9

DIGITAL INTERFACE/UTILITY BOARD CONNECTIONS—P/N 03-2115A01— -------------------- G-13

Summary ---------------------------------------------------------------------------------------------- G-13 RS-232 Digital Interface Connections ------------------------------------------------------------ G-13 Additional Interface Connections------------------------------------------------------------------ G-14 Order Wire Audio Alignment ---------------------------------------------------------------------- G-14

APPENDIX H—MDS 4310-HL DATA TRANSCEIVER FOR USE IN HAZARDOUS LOCATIONS

INTRODUCTION ----------------------------------------------------------------------------------------------------- H-1 CONDITIONS OF APPROVAL ------------------------------------------------------------------------------------ H-1

APPENDIX I—CANADIAN CERTIFICATION

RSS APPROVALS ----------------------------------------------------------------------------------------------------- I-1 RESTRICTIONS-------------------------------------------------------------------------------------------------------- I-1

APPENDIX J—AUDIO PROCESSING MODULE

INTRODUCTION ------------------------------------------------------------------------------------------------------ J-1 SPECIFICATIONS ----------------------------------------------------------------------------------------------------- J-1 ALIGNMENT ----------------------------------------------------------------------------------------------------------- J-2 CONFIGURATION ---------------------------------------------------------------------------------------------------- J-2

TABLES

Table 2-1. DB-25 Interface Connector Pin Functions-------------------------------------------------------------- 2-6 Table 2-2. External Indicators For Radios Without Internal Modems ----------------------------------------- 2-11 Table 2-3. External Indicators For Radios WithInternal Modems---------------------------------------------- 2-12 Table 2-4. J11–External Interface TTL/RS-232 ------------------------------------------------------------------ 2-13 Table 2-5. J14 Receiver Audio Output Normal/Inverted -------------------------------------------------------- 2-13 Table 2-6. Signal Loss versus Cable Length and Type ---------------------------------------------------------- 2-16

Table 3-1. Diagnostic and Control Capabilities------------------------------------------------------------------- 3-10 Table 3-2. Programming and Test Commands-------------------------------------------------------------------- 3-11 Table 3-3. Hand-Held Terminal Operating Defaults ------------------------------------------------------------- 3-14

Table 4-1. Main Circuit Board Potentiometer Settings for Remote Maintenance------------------------------ 4-6 Table 4-2. Test Procedure Reference Chart ------------------------------------------------------------------------- 4-6

Table B-1. Settings for the MDS 4800 bps Modem’s Configuration Switch S1 ------------------------------ B-3 Table C-1. Settings for the MDS 9600 bps Modem’s Configuration Switch S1 ------------------------------ C-2 Table F-1. Interface Board J1 Connectors ------------------------------------------------------------------------- F-11 Table G-1. Interface Board TB1 Connectors -------------------------------------------------------------------- G-13 Table J-1. P/N 03–2301A01 Configuration Switch Settings ------------------------------------------------------ J-2

MDS 2141A01, Rev. A TABLE OF CONTENTS v

ILLUSTRATIONS

Figure 1-1. MDS 4310 Model Number Codes---------------------------------------------------------------------- 1-4 Figure 1-2. Printed Circuit Model Number Location -------------------------------------------------------------- 1-5 Figure 1-3. MDS 4310 Transceiver—Major Assemblies -------------------------------------------------------- 1-13

Figure 2-1. Mounting Dimensions—Front View------------------------------------------------------------------- 2-3 Figure 2-2. Mounting Dimensions—Bottom View ---------------------------------------------------------------- 2-3 Figure 2-3. External Connections------------------------------------------------------------------------------------- 2-5 Figure 2-4. Received Signal Strength Indicator Calibration Chart (Typical)---------------------------------- 2-10 Figure 2-5. Location of Configuration Jumpers ------------------------------------------------------------------- 2-12 Figure 2-6. Detail of Configuration Jumpers—J14 --------------------------------------------------------------- 2-13

Figure 3-1. Hand-Held Terminal Connected to the MDS 4310 Transceiver ----------------------------------- 3-2 Figure 3-2. MDS 4355 Packaged Transceiver---------------------------------------------------------------------- 3-2 Figure 3-2. Hand-Held Terminal Keypad --------------------------------------------------------------------------- 3-6 Figure 3-3. HHT Initialization Display ----------------------------------------------------------------------------- 3-13 Figure 3-4. DB-25 Interface Adapter Wiring ---------------------------------------------------------------------- 3-14 Figure 3-5. DB-9 to DB-25 Interface Cable Wiring -------------------------------------------------------------- 3-15 Figure 3-6. DB-25 to DB-25 Interface Cable Wiring------------------------------------------------------------- 3-15

Figure 4-1. Remote Data Terminal Emulator Wiring-------------------------------------------------------------- 4-4 Figure 4-2. Construction Options for Building a Data Terminal Emulator------------------------------------- 4-4 Figure 4-3. VCO Lock Voltage Test Point-------------------------------------------------------------------------- 4-9 Figure 4-4. 1200 bps AFSK Modem -------------------------------------------------------------------------------- 4-13 Figure 4-5. 4800 BPS FSK Modem--------------------------------------------------------------------------------- 4-15 Figure 4-6. 9600 BPS FSK Modem--------------------------------------------------------------------------------- 4-17 Figure 4-7. Remote Maintenance Module-------------------------------------------------------------------------- 4-19 Figure 4-8. Remote Maintenance Screen--------------------------------------------------------------------------- 4-23 Figure 4-9. MDS 4310 Transceiver PC Board Test Points and Adjustments --------------------------------- 4-25

Figure 5-1. MDS 4310 Transceiver Block Diagram --------------------------------------------------------------- 5-7 Figure A-1. 1200 bps Modem PC Board --------------------------------------------------------------------------- A-1 Figure A-2. Bell 202T Compatible Modem Block Diagram----------------------------------------------------- A-3

Figure B-1. MDS 4800 bps Modem Block Diagram -------------------------------------------------------------- B-2 Figure B-2. MDS 4800 bps Modem Assembly Diagram --------------------------------------------------------- B-3

Figure C-1. MDS 9600 bps Modem Block Diagram -------------------------------------------------------------- C-3 Figure C-2. 9600 bps Modem Assembly Diagram----------------------------------------------------------------- C-3

Figure D-1. Remote Maintenance Module, P/N 03-1958A01--------------------------------------------------- D-2 Figure E-1. Order Wire Module -------------------------------------------------------------------------------------- E-1

Figure E-2. Order Wire Board Component Layout ---------------------------------------------------------------- E-2 Figure E-3. Order Wire Block Diagram ----------------------------------------------------------------------------- E-3

Figure F-1. MDS 4350 Interior View-------------------------------------------------------------------------------- F-1 Figure F-2. MDS 4350 Features & Dimensions-------------------------------------------------------------------- F-2 Figure F-3. 03-1105A21 Keying Options, Analog Interface Assembly----------------------------------------- F-6 Figure F-4. MDS 4350 Packaged System Wiring Diagram ------------------------------------------------------ F-7

vi TABLE OF CONTENTS MDS 2141A01, Rev. A

Figure F-5. Analog Interface Assembly 03-1105A21------------------------------------------------------------- F-9 Figure F-6. MDS 4350 Packaged System Wiring Diagram

with 03-1467A21 RS-232/TTL Interface ---------------------------------------------------------- F-13

Figure F-7. RS-232/TTL Interface Assembly 03-1467A21 ---------------------------------------------------- F-15 Figure G-1. MDS 4355 Interior (AC Version) with Fiberglass Enclosure Removed------------------------- G-1

Figure G-2. MDS 4355 Dimensions, Feed-Through Couplings & Mounting Points ------------------------- G-2 Figure G-3. Exploded View of DC Version of System ----------------------------------------------------------- G-3 Figure G-4. Exploded View of AC Version of System ----------------------------------------------------------- G-4 Figure G-5. Plugs for Primary Power TB2 and Interface TB1 Connectors ------------------------------------ G-7 Figure G-6. Keying Options for the 03-2110A01 Analog Interface/Utility PC Board --------------------- G-10 Figure G-7. MDS 4355 Packaged System Wiring Diagram

with the 03-2110A01 Analog Interface/Utility Board ------------------------------------------ G-11 Figure G-8. Analog Interface Assembly 03-2110A01 ---------------------------------------------------------- G-12 Figure G-9. MDS 4355 Packaged System Wiring Diagram ith the

03-2115A01 RS-232 Digital Interface & Utility PCB ------------------------------------------ G-15 Figure G-10. RS-232 Digital Interface and Utility Board ------------------------------------------------------ G-16

Figure J-1. Audio Processing Module Installation Diagram ------------------------------------------------------ J-1 Figure J-3. 03-2301A01 Audio Processing Module---------------------------------------------------------------- J-2

MDS 2141A01, Rev. A TABLE OF CONTENTS vii

About This Manual

This manual covers three models in the MDS 4300 Series of 450 MHz radio transceivers. The MDS 4310 is the basic transceiver, and it is the main focus of this manual. The MDS 4350 and MDS 4355 are packaged weatherproof models, which include the MDS 4310 radio plus a power supply, back-up battery and interface/utility board, all mounted in a NEMA 4 enclosure. Appendix F of this manual covers the main features of the MDS 4350 and Appendix G covers the MDS 4355. All discussions relating only to the MDS 4350 and MDS 4355 Packaged models will be clearly marked.

The following is a brief summary of the contents in each chapter of the manual. Chapter 1—General, provides a general introduction to the MDS 4310 Transceiver and its

standard and optional equipment. A specifications table provides a detailed summary of the radio’s electrical and mechanical features.

Chapter 2—Installation,

4310 Transceiver. Recommendations are also provided for feedline and antenna selection, connection to external equipment, jumper configuration settings and other requirements for planning a successful radio installation.

Chapter 3—Programming and Diagnostics, gives procedures for connecting a Hand-Held Terminal, or a standard ASCII Terminal to the radio for accessing and controlling the transceiver’s operating parameters and performing diagnostic checks.

Chapter 4—Field Tests and Alignments, contains detailed procedures for testing and adjusting the equipment to ensure maximum performance. The procedures here are not required for normal installations, but can be performed as an aid in diagnosing a suspected problem, or following replacement or repair of an assembly.

Chapter 5—Theory of Operation, provides an overview of the circuits comprising the MDS 4310 Transceiver. The text is supported with an oversized block diagram at the end of the chapter to aid in understanding the material.

Chapter 6—Troubleshooting System Problems,

procedures for system troubles, and suggests possible solutions.

contains steps for installation, hookup and checkout of the MDS

contains recommended evaluation

viii TABLE OF CONTENTS MDS 2141A01, Rev. A

CHAPTER 1—GENERAL

INTRODUCTION

The MDS 4310 Transceiver offers continuous duty, high-performance data communications in the 390–470 MHz frequency band. The transceiver is fully synthesized and can be programmed to operate on 12.5 kHz and 25 kHz channels within this range.

The MDS 4310 Transceiver can be supplied with a MDS 2314Axx main PC board or a MDS 2013Axx main PC board. Although the two PC boards are similar, this manual covers transceivers with the 2314Axx main PC board. Refer to the MDS 05-2141A01 manual for specific information regarding transceivers equipped with the 2013Axx main PC board.

The Transceiver’s design is highlighted by a compact and rugged die-cast aluminum case which houses the basic RF unit, and all diagnostic and modem options. The MDS 4350 and MDS 4355 are alternate weatherproof models which include the MDS 4310 radio plus a power supply, back-up battery and interface/utility board, all mounted in a NEMA 4X enclosure. Appendix F of this manual covers the main features of the MDS 4350 and Appendix G covers the MDS 4355 Package.

The contents of this manual center on the MDS 4310 Data Transceiver. All discussions relating only to the MDS 4350 and MDS 4355 Packaged models are clearly marked.

TRANSCEIVER

MDS 2000 DATA TRANSCEIVER

+ –

The MDS 4310 Data Transceiver The MDS 4350 Packaged Radio

(MDS 4355 Similar in appearance)

APPLICATIONS

The MDS 4310 Data Transceiver is a single channel, half-duplex, radio designed for use in multiple address systems (MAS) such as those licensed under Part 90 of the Federal Communications Commission rules, with an emission designation of F1D, F2D, or F3D, depending on application and configuration.

Continued on next page.

MDS 05-2415A01, Rev. A 1-1

As a component of point-to-multipoint data telemetry systems, the MDS 4310 Transceiver is well suited for such applications as:

• Supervisory Control and Data

Acquisition (SCADA)

• Telemetry Systems

• Energy Distribution Automation

MDS 4000 Series radio systems offer the advantage of a frequency band which in many areas is specially coordinated to provide protection from co-channel interference. Because these are primarily data-only channels, voice users are not likely to interfere with data transmission and reception.

TERMS “ANALOG” AND “DIGITAL”

In all MDS literature, the terms “analog” and “digital” are commonly used to describe the modulation modes and other signal characteristics of various products. The following are examples of how these terms are commonly used in this manual.

Analog Modem, Analog Radio, Analog Mode— These terms relate to equipment or operating modes using linear frequency modulation and detection techniques. The circuitry handles analog communication signals, such as audio frequency shift keying (AFSK) or analog voice frequency signals through the system. Generally, these products or modes operate in the 50 to 1200 bits per second (bps) data range in non-voice applications. Modulation sources include an internal MDS brand 1200 bps modem or external 4-wire audio sources such as AFSK modems.

Digital Modem, Digital Radio, Digital Mode— These terms relate to equipment or operating modes using non-linear frequency shift keying modulation and detection techniques. The signal may alternate between two or three discrete frequencies (FSK) depending on equipment configuration. Generally, these products or modes operate in the 4800 and 9600 bps range.

• Information Systems

• Oil Fields and Pipelines

• Alarm Monitoring

• Security

MDS 4310 MODULATION TECHNIQUES

The MDS 4310 Transceiver can be modulated by either audio frequency shift keying (AFSK) or frequency shift keying (FSK) controlled directly by the digital output of the MDS internal modems. Alternatively, an external modem can be used for controlling AFSK transmission.

The MDS 4310 is capable of interfacing with data equipment at standard rates between 50 and 4800 bits per second (bps) with an asynchronous interface to the local terminal unit. The MDS 4310 provides a synchronous or asynchronous interface at data speeds of 1200, 4800 and 9600 bps with one of the optional FSK modems installed internally.

MICROCONTROLLER FEATURES

The MDS 4310 Transceiver features an internal microcontroller that allows user programming and control of operating parameters and interrogation of diagnostic data. Programming of radio settings and monitoring of operating parameters can be done with a terminal unit connected through the transceiver’s DB-25 INTERFACE connector, eliminating the need to remove the radio from its mounting position or open its top cover. The terminal can be either an MDS-supplied Hand-Held Terminal (HHT), or an IBM PC (or compatible) personal computer running MDS-supplied software, or other PC-based communications

1-2 GENERAL MDS 05-2415A01, Rev. A

software (such as PCPLUS™, PROCOMM™, PCTALK™, etc.). As a third alternative, any terminal with an RS-232 serial port can also be used.

With one of these devices connected, the user can program the transmit and receive frequencies, RTS/CTS delay time, PTT delay, soft carrier dekey, time-out-timer, loopback code and the MDS-patented Squelch Tail Eliminator circuit. In addition, an internal message field (up to 27 characters) can be entered to label each transceiver with its own identity. Password security and several other functions are also programmable.

Diagnostic functions that can be measured through the diagnostic module include received signal strength indication (RSSI), various critical voltage levels, internal temperature, forward power, and antenna/feedline VSWR. When equipped with the remote maintenance module and used in a system with an MDS 4100 Series Master Station, several of these diagnostic measurements can be sent over-the-air back to the master station for display by the associated PC diagnostic software.

The internal micro-controller also provides basic indication of operating parameters and values. While not a substitute for calibrated test equipment, this is useful for quick field evaluations.

SOFT CARIER DEKEY

This feature can be used to keep the transmitter keyed for a short period of time (typically up to 5 ms) after the last data bit has been transmitted. This period of silence provides a clear indication that the message has ended and helps ensure no errors are introduced into the data stream as a result of the transmitter unkeying too soon. The soft carrier dekey feature can be selected or modified by using the HHT.

CONTROL INPUTS AND OUTPUTS

Four control inputs and outputs are provided on the MDS 4310 Data Transceiver’s 25-pin “D” INTERFACE connector. They are:

1. Receiver Squelch. This output goes low when the receiver is squelched, and is

pulled high when the receiver squelch is open. When the squelch is open, this pin supplies +8 Vdc through a 1 kΩ resistor.

2. Out-of-Lock Alarm. When this output is low (less than 0.5 Vdc), it indicates normal

operation. A logic high (greater than 4 Vdc) indicates a failure in the phase lock loop signal source, or a transmitter time-out condition.

3. Received Signal Strength Indicator. This analog signal output supplies a received

signal strength indicator (RSSI) voltage on Pin 21 of the DB-25 connector. The RSSI voltage is proportional to the strength of the signal present at the antenna connector, and provides a useful indication of signal levels between –120 dBm and –60 dBm. This can be especially helpful during installation to aid in aiming the station antenna for maximum received signal strength.

4. Radio Disable. When this input on Pin 12 of the

INTERFACE connector senses a

ground, it disables or “turns off” most circuits in the radio, including transmit, receive, modem and diagnostic functions. This reduces power consumption, yet preserves the radio’s ability to be brought quickly online. Total current drain in the disabled state is less than 14 mA.

The annunciator or LED indicator panel on the transceiver’s face shows the radio’s basic performance without removing the housing cover. For transceivers without a built-in modem, front-panel indicators are provided for primary power on, receive carrier detect, out-of-lock

MDS 05-2415A01, Rev. A GENERAL 1-3

alarm, transmit keyline activity and transmit status. When used with the modem option, an annunciator panel indicates the status of the RS-232 interface lines (TXD, RXD, DCD, RTS, CTS). If desired, the LED display can be turned off by moving a jumper inside the radio. This may be desirable in applications where power consumption must be kept to an absolute minimum.

MODEL NUMBER CODES

The model number as found on the serial number label may be used to determine the general hardware configuration of the radio as it was shipped from the factory. Figure 1-1 illustrates the significance of the various characters in the radio’s serial number. The serial number label is located on the end of the radio enclosure.

OPERATION

(R) Base/Remote

POWER SETTING

(1) 12VDC

INTERFACE

(0) 4-Wire Audio (2) 1200 BPS (A) 4800 BPS (D) 9600 BPS

4310RN 15

DIAGNOSTICS

(0) None (4) Remote Maint.

BANDWIDTH

(1) 12.5 KHz

SEPARATION

(5) 5–10 MHz/Simplex

● ●●●●

REGULATORY CERTIFICATION

(0) N/A (1) FCC (USA) (2) DOC RSS-119 (3) DOC RSS-122 (Canada)

This information is subject to configuration and change. Contact MDS to verify certification.

FREQUENCY RANGE

(A) 390–406 MHz* (E) 450–470 MHz* (F) 406–430 MHz* (G) 350–370 MHz (H) 370–390 MHz (I) 390–410 MHz

* 2013 printed circuit board only

(J) 406–430 MHz (K) 430–450 MHz (L) 450–470 MHz (M) 470–490 MHz (N) 490–512 MHz

●

SAFETY CERTIFICATION

(0) N/A (F) Factory Mutual / UL

Figure 1-1. MDS 4310 Model Number Codes

MAIN PRINTED CIRCUIT BOARD PCB VARIATIONS

The MDS 4310 Transceiver may be equipped with a 2314Axx main PC board or a 2013Axx main PC board. The significant difference is the frequency range. Although the two PC boards are similar, this manual covers transceivers with the 2314Axx main PC board which has a frequency range of 350 to 512 MHz. Refer to manual part number MDS 05-2141A01 for specific information regarding transceivers equipped with the 2013Axx main PC board which has a frequency range of 390 to 470 MHz. See Figure 1-2 for the location of the main PCB part number label.

The main PC board part number can be identified without removing the housing cover. Refer to Figure 1-1 to determine the transceiver frequency range. The frequency ranges identified with a G, H I, J, K, L, M or N are equipped with the 2314Axx main PC board. The main PC board part number can also be determined by using the

HREV command via the HHT or

terminal. The HREV command displays the main PC board part number and the revision level. The nominal frequency operating range of the transceiver PCB can also be determined by

using the

MOD command via the HHT or terminal. The MOD command displays the main PC

board model number and the revision level. See Chapter 3 –Programming and Diagnostics for detailed information on the use of the

Hand-Held Terminal.

1-4 GENERAL MDS 05-2415A01, Rev. A

PRINTED CIRCUIT

BOARD MODEL

LABEL

341

1 2 3

Figure 1-2. Printed Circuit Model Number Location

SPECIFICATIONS: MDS 4310 DATA TRANSCEIVER (2314 MAIN PC BOARD)

General

Frequency Range: 350–512 MHz (Nominal) Operating Bands— 350–370 MHz, 370–390 MHz, 390–410 MHz,

any one of eight: 406–430 MHz, 430–450 MHz, 450–470 MHz,

470–490 MHz, and 490–512 MHz

Frequency Programming: Programmable in 6.25 kHz increments to any

channel pair in radio operating sub-band.

TX/RX Spacing: 0 (Simplex), 5 MHz, 10 MHz standard; others

are possible, consult with factory.

Primary Power—

Model 4310 Transceiver

Voltage: 13.8 Vdc Nominal

(10.5–16.5 Vdc Operating Range)

TX Supply Current: 2.0 A typical, 2.5 A Maximum, at 13.8 Vdc

Varies with power output adjustment

RX Supply Current: 65 mA typical, without options installed or

LED indicators turned OFF Standby Current (Radio Inhibited) : 14 mA maximum Connector: Integral part of power cable assembly

(Six foot/1.8 meter cable assembly included) Fuse: 3.0 A, 3AG, FB (Fast Blow);

Holder part of cable assembly Reverse Polarity Protection: Diode across primary power input with

internal 4 A plug-in fail-safe fuse.

Continued on next page.

MDS 05-2415A01, Rev. A GENERAL 1-5

General Continued

Model 4350 and 4355 Packaged Radios

Voltage: 120/220 Vac with 5 ampere-hour

Battery Back-up (Standard) 12, 24, 48, & 125 Vdc (Optional)

DC Supply: Positive, Negative;

Floating Ground with 24, 48, & 125 Vdc TX Power Consumption: 50 watts maximum at rated output RX Power Consumption: 5 watts maximum Transient Protection: 2500 Volt Isolation on Voice Frequency (VF)

Inputs and Outputs, Power Supply & Keying

Dimensions:

Model 4310 Transceiver 2.0" x 5.62" x 7.25"

50 x 143 x 184 mm

(Not including mounting hardware or

connector housings)

Model 4350 Packaged Radio 9.5" x 17.5" x 19.5"

241 x 445 x 495 mm

(Not including mounting hardware or

connector housings)

Model 4355 Packaged Radio 6.5" x 11.85" x 13.75"

165 x 301 x 350 mm

(Not including mounting hardware or

connector housings)

Weight:

Model 4310 Transceiver Maximum 3.5 Lbs./1.6 kg

w/all options installed

Model 4350 Packaged Radio Maximum 33 Lbs/15.0 kg

w/all options installed

Model 4355 Packaged Radio Maximum 21 Lbs/9.53 kg

w/all options installed

Transmitter

Frequency Range: 350–512 MHz (Nominal) Operating Bands— 350–370 MHz, 370–390 MHz, 390–410 MHz,

any one of eight: 406–430 MHz, 430–450 MHz, 450–470 MHz,

470–490 MHz, and 490–512 MHz

Frequency Programming: Programmable in 6.25 kHz increments to any

channel pair in radio operating sub-band.

TX/RX Spacing: 0 (Simplex), 5 MHz, 10 MHz standard; others

are possible, consult with factory.

1-6 GENERAL MDS 05-2415A01, Rev. A

Power Output: 5 Watts/+37 dBm (standard)

at the ANTENNA Connector

Adjustable down to 0.5 watt/+27 dBm Duty Cycle: 100%/Continuous Output Impedance: 50 Ohms Forward & Reflected Power Detector: Built-in Frequency Stability: ± 0.00015% (1.5 PPM), –30°C to +60° C,

For All Models RF Channel Bandwidth: 12.5 kHz (25 kHz Compatible) Spurious & Harmonic Emissions: –65 dBc TX Response Time: ≤ 4 ms Modulation Type: FSK—With 4800 and 9600 bps modems

FM—With 1200 bps AFSK modem Deviation: ±2.5 kHz Maximum Time-Out Timer: Internal; Programmable from 1–255 Seconds,

or Off Analog Model Audio Input

Characteristics—

Level: Adjustable, –20 to +10 dBm

for 2.5 kHz Deviation

Model 4310: 600 Ohms, Unbalanced

Model 4350: 600 Ohms, Balanced,

4-Wire Audio

Frequency Response: Model 4310: +1 dB, –3 dB, 50–3000 Hz

Model 4350: +1 dB, –3 dB, 300–3000 Hz

Soft Carrier Dekey: Programmable from 0 to 255 ms in 1 ms steps

Soft Carrier Dekey factory set to…

0 ms with no internal modem 0 ms with MDS 1200 baud modem 2 ms with 4800 FSK internal modem 4 ms with 9600 FSK internal modem

Transmitter Keying: Positive-going and negative-going,

TTL-compatible keying inputs are provided.

Inputs will operate with signal voltages

between 5 and 40 volts. Dry contact closures

are also suitable. Keyline input pins have an

input impedance of 10 kilohms and have built-

in over-voltage protection up to ±40 volts.

PTT Delay: Programmable from 0-31 ms in 1 ms steps

MDS 05-2415A01, Rev. A GENERAL 1-7

Receiver

Frequency Range: 350–512 MHz (Nominal) Operating Bands— 350–370 MHz, 370–390 MHz, 390–410 MHz,

any one of eight: 406–430 MHz, 430–450 MHz, 450–470 MHz,

470–490 MHz, and 490–512 MHz

Frequency Programming: Programmable in 6.25 kHz increments to any

channel pair in radio operating sub-band.

Type: Double Conversion Superheterodyne Frequency Stability: ±0.00015% (1.5 PPM) –30° to +60° C,

For All Models

Sensitivity for Analog Models: 12 dB SINAD at –117 dBm (0.3 µV) (at ANTENNA connector) w/de-emphasis OFF

12 dB SINAD at –119 dBm (0.25 µV)

w/de-emphasis ON

Bit Error Rates: Analog/AFSK at 1200 bps:

–6

BER 1x10

at –110 dBm

Digital/FSK at 4800 bps:

–6

BER 1x10

at –110 dBm

Digital/FSK at 9600 bps:

–6

BER 1x10

at –108 dBm Intermodulation: 75 dB Minimum (EIA) IF Selectivity: 100 dB minimum at Adjacent Channel

(± 25 kHz, one generator method, 20 dB quieting)

Desensitization: 70 dB minimum (EIA) on 25 kHz channels

65 dB minimum (EIA) on 12.5 kHz channels

Spurious and Image Rejection: 85 dB Minimum Analog Audio Output Characteristics—

Frequency Response (Refer. to 1 kHz): Model 4310—Basic Transceiver:

Filtered, +1, –3 dB, 50 – 3000 Hz Model 4310—with VOX Board:

Filtered, +1, –3 dB, 50 – 3000 Hz Unfiltered, +1, –3 dB, 50 – 4500 Hz

Model 4350: Filtered, +1, –3 dB, 300 – 3000 Hz

Level: Adjustable, – 20 to + 5 dBm

Model 4310: 600 Ohms, Unbalanced

Model 4350/55: 600 Ohms, Balanced Harmonic Distortion: < 3%, All Models, Measured w/de-emphasis RF Channel Bandwidth: 12.5 kHz (25 kHz compatible) Received Signal Strength Indicator (RSSI): Built-in, Range: –120 dBm to –60 dBm Squelch Opening Time: 2 ms

1-8 GENERAL MDS 05-2415A01, Rev. A

Diagnostics & Programming Interface (through INTERFACE connector)

Signaling Standard: RS-232C Interface Connector: DB-25

I/O Devices: • MDS Hand-Held Terminal

• IBM PC or compatible computer with CGA, EGA, VGA or Hercules Graphics™, DOS 2.0 or later and 640K of memory.

System Data Characteristics (through

INTERFACE connector)

Signals: without modem

Transmit Audio Input Filtered Receiver Audio Output Receiver Unsquelched Sensor (RUS) Received Signal Strength Indicator (RSSI) Out-of-Lock Alarm

PTT/PTT

added with internal modem

RS-232 Compatible Data Lines RXD TXD RTS CTS DCD DSR ETC* TC* RC*

* w/synchronous FSK only

Data Rates—

AFSK: 50 to 9600 bps—Asynchronous audio

interface using external modems 30 to 1200 bps—Asynchronous w/internal

Bell 202T compatible modem

FSK: 50 to 4800 bps—Asynchronous, w/internal

direct FSK interface 4800 bps—Async/Synchronous, w/internal

direct FSK interface 9600 bps—Async/Synchronous, w/internal

direct FSK interface

Data Turn-Around Time: 10 ms, including RTS/CTS time delay with

internal modem installed

CTS Delay: 5 to 255 ms,

Programmable in 1 ms increments

MDS 05-2415A01, Rev. A GENERAL 1-9

Environmental

Temperature Range: Full Performance: –30°C to + 60°C

Operational Performance: –40°C to +70°C

Humidity: 95% at + 40°C Non-Condensing Case: Model 4310–Die-Cast Aluminum

Model 4350–Die-cast aluminum inside a NEMA 4 Outdoor Housing, w/Padlockable Latches

Model 4355–Die-cast aluminum inside a NEMA 4 Outdoor Housing, w/Padlockable Latches

AGENCY APPROVALS

FCC: Part 15.247 FCC approved Underwriters Laboratories (UL)*: UL Approval for Class 1, Div. 2; Groups

A, B, C and D; hazardous locations

Factory Mutual (FM)*: FM Approval for Class 1, Div. 2; Groups

A, B, C and D; hazardous locations

* These certifications available on special orders.

FCC INFORMATION (USA)

†

PART 90 Transmitter Model: E5M5LL2013 Channel Capacity: 1 Frequency Tolerance: ±0.00015% Output Power :

(Continuously Variable) 0.1 to 2 watts 0.1 to 5 watts Necessary Bandwidth: 12.5 kHz 25 kHz Emission Designators: F1D: 16K0 16K0

F2D: 16K0 16K0 F3D: 16K0 16K0

†

Contact MDS for information on availability and governmental approvals in other countries.

OPTIONAL EQUIPMENT, ACCESSORIES and CERTIFICATIONS

The MDS 4310 Data Transceiver can be supplied with the following options. For information on adding options to MDS radios, please contact the MDS Marketing Department.

Special Certifications

Some models of the MDS 4300 Series transceivers are available with either Factory Mutual (FM) or Underwriter’s Laboratory (UL) Approval for operation in Class I, Groups ABCD,

1-10 GENERAL MDS 05-2415A01, Rev. A

Division 2, hazardous locations. Please consult with the MDS Marketing Department for further information on these models.

1200 BPS Bell 202T Modem (Internal)—P/N 03-1815A01

The internal AFSK Bell 202T compatible modem is available for low speed data requirements. It is used at slower standard speeds (30–1200 bps) and provides compatibility in a radio system operating with non-MDS brand analog radios. A standard RS-232 C or TTL compatible interface is provided through the radio’s

INTERFACE (DB-25) connector.

4800 BPS Modem(Internal)—P/N 03-1831A01

This intermediate speed digital FSK interface (50–4800 bps asynchronous or 4800 bps synchronous) can be used in any MDS 4300 Series remote radio. It is compatible with MDS 4100 Series digital master station radios using this modulation technique.

A standard RS-232 or TTL compatible interface is provided through the radio’s

INTERFACE

(DB-25) connector.

9600 BPS Modem (Internal)—P/N 03-1833A01

The MDS internal 9600 bit per second (bps) FSK modem provides synchronous or asynchronous operation where high speed data exchanges are required. The modem is compatible only with MDS 4100 Series digital master station radio systems operating at 9600 bps. Available with RS-232 or TTL interface provided through the radio’s

INTERFACE

(DB-25) connector.

Audio Processing Module (Internal)—P/N 03-2301A01

The Audio Processing Module can be installed to support applications where no keying circuits are provided by a modem or remote terminal unit (RTU). The assembly senses the presence of a tone on the transmit audio line and keys the transmitter. The VOX assembly provides for audio signal pre-emphasis and de-emphasis if needed. This option is mounted in the Option 1 position on the transceiver’s main board. See Appendix J.

Order Wire Module (External)—P/N 02-1297A01

The Order Wire Module option is supplied as an external device that plugs into the radio’s

INTERFACE (DB-25) connector. It can be used with a standard four-pin modular telephone

handset to provide a temporary voice link back to the master site for installation and test purposes.

The order wire uses a voice-operated transmit (VOX) circuit to key the transmitter when the operator speaks into the handset. Otherwise, normal operation of the remote transceiver continues since the order wire option is installed in-line between the transceiver and the RTU/modem. See Appendix E.

Remote Maintenance Module (Internal)—P/N 03-1958A01

With a Remote Maintenance Module installed in the Option 2 slot, three levels of diagnostics are available—Mode 1: Local Diagnostics, Mode 2: Advanced Diagnostics, and Mode 3: Remote Maintenance.

Continued on next page.

MDS 05-2415A01, Rev. A GENERAL 1-11

Remote Maintenance Module Continued

When Mode 1 (Local Diagnostics) is enabled, the following parameters are available:

• RSSI

• Forward and reflected transmit power

• VSWR

• Transceiver internal ambient temperature

• Phase lock loop (PLL) lock condition

• Primary power and internally regulated voltages

This information is available locally through the HHT or a PC running MDS Remote Diagnostic software (P/N 06-1972A01)

In Mode 2: Advanced Diagnostics mode, the diagnostics information available locally can also be retrieved over-the-air through an MDS 4100 Series Master Station. The results are displayed on a personal computer running MDS 2000 Diagnostics and Control System software.

Mode 3: Remote Maintenance provides the highest level of diagnostics capability. When Remote Maintenance is enabled, all of the above features are available plus local or over-theair control of the following parameters:

• RF Power Output Setting

• Frequency Offset

• Modem Data Deviation

Certain hardware elements must be present in the Remote and Master Stations for the Remote Maintenance feature to be enabled. Also, the transceiver must be properly programmed at the factory, or in the field using the HHT or a PC. If you ordered your radio system with Remote Maintenance capability, all of these elements will have been installed and tested at the factory.

If Remote Maintenance is being added to the system, refer to the instructions included with the upgrade kit for detailed installation procedures (Publication Number 05-2104A01). Consult the factory if you have questions regarding the capabilities of your existing system.

When using Remote Maintenance over the radio link, MDS 2000 Diagnostics and Control Software is required. Refer to the instructions included with the software for detailed installation procedures (Publication Number 05-1919A01).

Hand-Held Terminal Kit (External)—P/N 02-1501A01

The Hand-Held Terminal (HHT) allows the service technician to make certain key performance checks on the transceiver without removing the radio from its mounting position, and without the need for additional test equipment. In addition, the user can program the receive and transmit frequencies in the field, as well as other parameters.

Refer to Chapter 3 for information on connecting and using the HHT.

RS-232 to RS-422 Converter Assembly—P/N 01-2358A01

An optional RS-232 to RS-422 adapter plug (P/N 01-2358A01) is available to allow direct connection of an RS-422 circuit to the

INTERFACE connector of a radio configured for RS-232

operation. An RS-422 connection may be required if the length of the interface cable exceeds 50 feet (15.24 meters).

1-12 GENERAL MDS 05-2415A01, Rev. A

TTL to RS-232 Converter Assembly—P/N 03-2223A01

An optional TTL to RS-232 converter is available to allow direct connection of RS-232 equipment (such as an RTU or HHT) to a radio that has been configured for TTL operation. This unit connects between the transceiver

INTERFACE connector and the external equipment,

making the transceiver appear as an RS-232 device.

TOP COVER

COVER SCREWS

OPTION 1— Modem PC Assembly or

Audio Processing Module OPTION 2—

Remote Maintenance Module or Diagnostic & Loopback Module

TRANSCEIVER PC BOARD

INTERFACE

CONNECTOR

LED ANNUNCIATOR

DISPLAY DC POWER

INPUT

ANTENNA

DETACHABLE & ADJUSTABLE

MOUNTING BRACKETS (2)

Figure 1-3. MDS 4310 Transceiver—Major Assemblies

BOTTOM COVER

MDS 05-2415A01, Rev. A GENERAL 1-13

This page intentionally blank

1-14 GENERAL MDS 05-2415A01, Rev. A

CHAPTER 2—INSTALLATION

DANGER

The MDS 4310-HL Data Transceiver is approved for use in Class I, Groups ABCD, Division 2, Hazardous Locations. The installer of these transceivers MUST be familiar with hazardous location installation guidelines before installation or maintenance is begun. Do not begin installation of or make external connections to this device unless the area is known to be non-hazardous.

Refer to Appendix H of this manual for further information on the approved conditions under which the MDS 4310-HL can be installed in hazardous locations.

OVERVIEW

The MDS 4310 data transceiver is designed to be part of a data communications system. Three critical objectives must be met during the installation—a good antenna system, adequate stable primary power and the correct interface between the transceiver and the external data equipment.

MDS 4310 transceivers are shipped with final test data sheets from the Manufacturing Test Department. The test data sheets contain radio hardware and software configuration information and actual performance measurements. Included in the data sheets are the transmit and receive frequency (as measured), receive sensitivity, transmitter power output and modulation characteristics, as well as pre-programmed loopback code. In most cases, the transceiver requires no alignment during installation.

The following installation steps are for a typical installation.

1. Install the antenna transmission line, and preset the antenna heading.

2. Mount the transceiver vertically or horizontally on a stable surface.

3. Measure and install the primary power for the transceiver.

4. Verify that the unit serial number and loopback code are the same as found on the test data sheet.

5. Verify that the transceiver’s operating frequencies are as listed on the operating license. Check the license against the measured frequencies shown on the test data sheet.

6. Verify interface requirements and protocol—

If no modem is installed…

• Check the transmit audio input level.

• Check the receive audio output level.

• Check the keyline operating characteristics—Ground or +5 Vdc can be used to key the transmitter. Make sure the correct pin is wired on the transceiver’s

INTERFACE connector.

MDS 05-2415A01, Rev. A 2-1

OVERVIEW Continued

If a modem is installed…

• Check the modem’s configuration switch, if applicable, to verify the modem configuration. (This applies to 4800 and 9600 bps modems only. Refer to tables B-1 and C-1 for switch settings.) Is it compatible with the external data equipment attached to the transceiver? The internal modem configuration is based on data collected from the customer when the order was placed.

• Will the external data equipment provide asynchronous or synchronous data? (This applies to 4800 and 9600 bps modems only.)

• Will the external data equipment operate with Data Set Ready (DSR) continuously held high? Most data equipment will, and this line is tied high inside the radio.

• Request to Send (RTS) functions as transmitter keyline.

7. Connect the antenna, primary power and external interface equipment as required to the transceiver.

8. Check the transceiver’s power output and antenna system VSWR (or reflected power).

9. Key the transmitter and optimize transmit and receive signals through refinement of the antenna heading.

10. Verify basic system operation by establishing data communications between the remote and the master stations.

This should complete the basic steps in the installation of the transceiver. More detailed information will follow in this chapter should the user experience difficulties or choose to make more detailed operational checks.

SURFACE MOUNTING

Using the supplied bracket, the MDS 4310 Data Transceiver can be mounted in any position inside heated or unheated equipment buildings. For outdoor mounting, the unit must be mounted in either a customer-supplied weatherproof housing or the MDS 4350/MDS 4355 packaged enclosure. The MDS 4310 die cast package withstands casual water, such as drips, occasional spills, or condensation, but it is not suitable for continuous exposure to rain or wind-driven moisture.

There are two mounting footprints that can be used. Choose the one that best suits your installation situation. See Figures 2-1 and 2-2 for details and dimensions.

NOTE

The mounting brackets must be fastened to the transceiver housing with #6-32 x 5/16 inch screws. Longer screws will penetrate the housing and damage the main printed circuit board.

2-2 INSTALLATION MDS 05-2415A01, Rev. A

To install the unit:

1. Choose a location to allow easy access to the fasteners so that the entire unit can be readily removed for service or replacement, yet allows viewing of the LED indicators on the front of the case.

2. Fasten the brackets to the mounting surface with a 1/4 inches (M6) bolt, screw, or lag screw (fasteners not provided) through the four holes in the mounting bracket.

3. If mounting surface is uneven, use three fasteners instead of four to prevent warping of the mounting bracket.

5.6 inches 143 mm

ANTENNA

KL TX RX

DC IN

57 mm

2.25 in.

2.0 in.

51 mm

INTERFACE

Figure 2-1. Mounting Dimensions—Front View

MOUNT BRACKETS WITH THESE TWO HOLES FOR ALTERNATE MOUNTING

USE ONLY #6-32 x 5/16 INCH SCREWS

70 mm

2.75 in.

6.75 inches 171 mm

7.25

inches

184 mm

8.5 inches 216 mm

Figure 2-2. Mounting Dimensions—Bottom View

MDS 05-2415A01, Rev. A INSTALLATION 2-3

EXTERNAL CONNECTIONS

The following section describes how to connect external equipment to the transceiver in typical installations. These recommendations may not be appropriate for all locations; local electric wiring or fire codes may prescribe unique standards. The US National Electrical Code is commonly the basis for local wiring guidelines and is recommended in the absence of local standards.

DANGER

The MDS 4310-HL Data Transceiver is approved for use in Class I, Groups ABCD, Division 2, Hazardous Locations. The installer of these transceivers MUST be familiar with hazardous location installation guidelines before any installation or maintenance is begun. Do not begin installation of or make external connections to this device unless the area is known to be non-hazardous.

Refer to Appendix H of this manual for further information on the approved conditions under which the MDS 4310-HL can be installed in hazardous locations.

ANTENNA Connector

ANTENNA Connector on the front panel of the MDS 4310 is the RF connector. See Figure

The 2-1. It is an industry standard female type “N” connector and mates with a standard type “N” male connector, such as Amphenol 3900 (MIL Type UG-21) for RG-8 cable.

The exact mating connector type depends on the cable used. If large diameter rigid or semirigid coaxial cable is used for the feedline (see Antenna and Feedlines section), use a short length of RG-8 or RG-214/U cable between the transceiver and the feedline. A three foot section of RG-214/U cable with connectors at both ends (P/N 19-1323A01) is available from MDS. This flexible interface eliminates tight bends in the feedline and reduces bending, mechanical stress on the feedline and connectors.

+13.8 DC (Primary Power) Connector

The radio can be powered from +13.8 Vdc power source connected through J2 on the transceiver’s front panel. A custom power cable with an integral fuse and a molded mating connector is provided with the radio. The lead with the integral fuse is the positive + line and the lead with no fuse is the negative – line.

This power cable has an in-line fuse rating of three amperes (3A); do not use a substitute

cable without providing some type of external current limiting (fuse) protection for the radio.

INTERFACE Connector

On the left side of the front panel is the

INTERFACE connector, J1, consisting of a standard 25-

pin female “D” style connector. It mates with male connectors of the same series, such as the ITT CANNON DB-25-P. These connectors are manufactured by many firms and are available from distributors or from most retail electronics stores.

2-4 INSTALLATION MDS 05-2415A01, Rev. A

NOTE

Do not use a full RS-232 cable for connection to the

INTERFACE

connector. Cross-coupling between wires in the cable can cause improper operation. Use only the pins required for the application. (Refer also to Note 2 in Table 2-1.)

INTERFACE

TR MR CD

TD IN RD

DATA AND

MODULA TION

INTERFACE

DC POWER

INPUT

13.8 VDC ANTENNA CONNECTOR &

TRANSMISSION LINE

13.8 VDC

ANTENNA

–

Figure 2-3. External Connections

Radios without internal modems…

INTERFACE connector allows a unbalanced 600Ω voice frequency interface to the radio

The with additional pins for transmitter keying (PTT), alarm, and diagnostic indications.

When an optional MDS internal modem is installed…

INTERFACE connector allows a standard RS-232 interface. The full handshake

The implemented includes TXD, RXD, RTS, CTS, and DCD. DSR is true whenever the radio and modem are powered up, and the transmitter is automatically keyed when RTS goes high. CTS is raised after the programmable delay (factory default is 10 ms), to allow time for the synthesizer to change frequency and for the receiver at the other end of the link to unsquelch. This time can be modified by the user to suit specific system timing requirements with the HHT.

When equipped with an optional internal modem, the MDS 4310 “SMART” Data Transceiver interfaces directly to any data terminal or RTU that supports the Bell 202, RS-232 format. This considerably simplifies installation, since the levels between the radio and modem can be preset at the factory, eliminating field measurements or adjustments. PTT control and delay are handled automatically by the radio with the RTS/CTS handshake. Even with the internal modem, the MDS 4310 “SMART” Data Transceiver allows programming and diagnostic information to be accessed without disassembly of the transceiver enclosure.

MDS 05-2415A01, Rev. A INSTALLATION 2-5

When using an internal modem, other pin functions of the DB-25 INTERFACE connector, such as PTT, Receive Audio, Transmit Audio and RSSI are still active and should normally be left open (unterminated). Connecting these pins to a computer terminal that also uses these pins for auxiliary connections can cause improper operation.

Pin connections for the transceiver’s

INTERFACE connector are summarized in Table 2-1 and

are described in greater detail later in this chapter.

NOTE

When using the TTL interface option, external 1 kΩ (1/8 W) pull-up resistors are required between J1 Pins 2, 3, 4, 5 & 6 and the logic source in the remote terminal unit (RTU).

Table 2-1. DB-25 Interface Connector Pin Functions

13 1

25 14

Viewed from Outside or from Plug’s Solder Cups

Pin Number and Function Pin Number and Function

1. Shield

2. Transmit Data In (TXD)*

3. Received Data Out (RXD)

4. Request-To-Send (RTS)*

5. Clear-To-Send (CTS)

6. Data Set Ready (DSR)

7. Signal Ground

8. Data Carrier Detect (DCD)

9. Transmit Audio Input*

10. Receiver Unsquelched Sense

11. Receiver Filtered Audio Output

12. Radio Disable*

13. Transmit Audio Output

14. Push-To-Talk (PTT)*

15. Transmit Clock (TC)

16. Push-To-Talk (PTT)

17. Receive Clock (RC)*

18. +13 Vdc

19. +8 Vdc

No Connection

20.

21. Received Signal Strength Indicator (RSSI)

22. Loopback Test–Receive Audio Input* (For local testing of loopback DTMF decoder)

23. Open Diagnostics

24. External Transmit Clock (ETC)*

25. Out-of-Lock Alarm

* Input

2-6 INSTALLATION MDS 05-2415A01, Rev. A

NOTES For Table 2-1

1. The radio is configured as DCE (data circuit-terminating equipment), as opposed to DTE (data terminal equipment).

2. When using an internal modem, other pin functions of the DB-25 INTERFACE connector, such as PTT, Receive Audio, Transmit Audio and RSSI, are still active and should normally be left open (unterminated). Connecting these pins to an external device such as a computer, RTU or PLC that also uses these pins for auxiliary connections can cause improper operation. The use of an interface cable that connects only the required pins is recommended.

3. Pins 1-8 are standard RS-232-C lines.

INTERFACE Connector Pin Functional Descriptions

The following description covers the

INTERFACE connector pin functions. The pin

descriptions are identical whether or not a modem is installed.

PIN 1: Shield

Connected to ground (negative supply potential) at the radio PC board.

PIN 2: TXD—Transmitted Data Input

without modem

This pin is connected to the data input port of the microcontroller and is used with an external programming terminal.

with internal modem

As above, this pin is also connected to the data input port (TXD) of the internal modem and is RS-232 compatible.

PIN 3: RXD—Received Data Output

without modem

This pin is connected to the data output port of the microcontroller and is also used with an external programming terminal.

with internal modem

As above, this pin also provides an RS-232 compatible output of data received by modem.

PIN 4: RTS—Request-To-Send Input

with internal modem

An RS-232 compatible input to modem which keys transmitter when RTS is at logic “high”.

PIN 5: CTS—Clear-To-Send Output

with internal modem

An RS-232 compatible output to external RTU or terminal, which goes “high” after the pre-programmed CTS delay time has elapsed.

MDS 05-2415A01, Rev. A INSTALLATION 2-7

PIN 6: DSR—Data Set Ready

Provides a + 8 Vdc DSR signal to external terminal through a 1 kΩ resistor.

PIN 7: Signal Ground

Connected to ground (negative supply potential) at the radio PC board.

PIN 8: DCD—Data Carrier Detect

with internal modem

Provides an RS-232 compatible output. Goes “high” when the modem detects a carrier from the master station.

PIN 9: Transmit Audio Input

without modem

The transmit audio input pin is normally connected to the audio output from the associated modem or RTU. The input impedance is 600 ohms, and the deviation is factory set so that an input level of –10 dBm produces a nominal transmitter deviation of 2.5 kHz. This is the correct deviation level for most 12.5 kHz systems and will also provide satisfactory service in most 25 kHz systems.

The deviation can be adjusted to fulfill the requirements of equipment using audio levels other than –10 dBm. See Chapter 3—Field Tests And Adjustments for detailed alignment procedures.

If the distance to the modem or RTU is greater than five feet (1.52 meters), use a twisted pair of conductors to connect the transmit audio circuit. Connect one end of the pair to the audio output terminals of the modem or RTU and the other end to Pin 9 and Pin 7 of the INTERFACE connector.

with internal modem

The order wire audio output appears on Pin 9 whenever the external order wire assembly is connected. Transmit audio from the modem is cut-off internally within the transceiver when order wire is in use. This applies only to

PTT. PTT

will not cut off the internal modem output.

PIN 10: Receiver Unsquelched Sense

This pin is not used in typical installations, but it is available as a convenience for special applications. It is pulled up to +8 Vdc through a 1 kΩ resistor whenever the receiver squelch is open, and pulled down to less than 1 Vdc when the squelch is closed. The output resistance of 1 kΩ should be considered when interfacing external equipment.

PIN 11: Receiver Filtered Audio Output—Line Level

This is the received audio output of the transceiver and is connected to the audio input of the external modem or RTU. It will drive a 600 ohm load; the output level is factory set to –10 dBm into 600 ohms for rated system deviation of

2.5 kHz on the received signal. Audio from the receiver discriminator is passed through a 3 kHz low-pass filter before it reaches this pin. This response is ideal for most external modems because it eliminates high frequency noise that can degrade the bit error rate performance of the modem. The audio response is nearly flat between 50 and 3000 Hz (no de-emphasis).

2-8 INSTALLATION MDS 05-2415A01, Rev. A

PIN 11: Receiver Filtered Audio Output—Line Level (Continued)

If the distance to the modem or RTU is greater than five feet (1.52 meters), use a twisted pair of conductors to make the connection. Connect one end of the pair to the audio input terminals of the modem or RTU and the other end to pins 11 and 7 of the INTERFACE connector.

PIN 12: Radio Disable

A ground on this point will totally disable the radio, including transmit, receive, modem and diagnostic functions. The pin controls the +8 Vdc used by all transceiver circuits. The I N LED is lit when Pin 12 of the INTERFACE connector is grounded. This input can be used to reduce power consumption during periods of non-use.

PIN 13: Transmitted Audio Output

with internal modem

This is the audio output of the modulator IC in the modem and is provided for test purposes.

PIN 14: PTT (Push-To-Talk )

This is one of two transmitter keying (PTT) inputs. The PTT input is normally at ground. When this pin is pulled up to greater than 4 volts, the transmitter is keyed; when the pin is at less than one volt (“open” circuit), the transmitter is off and the receiver is active. See pin 16 description.

PIN 15: TC—Transmit Clock

This pin is used only on applications requiring a synchronous interface. This pin provides a signal to clock transmit data bits out of the terminal connected to the radio. The Transmit Clock signal is compatible only with RS-232 interfaces.

PIN 16: Push-To-Talk (PTT)

This is an active-low PTT input, pin 16, it acts in the opposite way from pin 14; it is normally at 5 Vdc. When it is pulled down to less than one volt, the transmitter is keyed; when it is greater than 3 volts (“open” circuit), the transmitter is off.

PIN 17: RC—Receive Clock

This pin is used only on applications requiring a synchronous interface. This pin provides a clock signal to clock receive data bits from the radio to the terminal connected to the radio. The Receive Clock signal is compatible only with RS-232 interfaces.

PIN 18: +13 Vdc Unregulated Source

This pin provides a convenient source of unregulated 13 Vdc at 0.5 A for powering external low current equipment. This connection provides the primary power to the radio with no regulation. Excessive drain on this connection will blow fuse, F1, on the transceiver board.

MDS 05-2415A01, Rev. A INSTALLATION 2-9

PIN 19: +8 Vdc Regulated Source

This pin provides a convenient source of regulated 8 Vdc at 10 mA for powering external equipment.

PIN 20: No Connection PIN 21: RSSI (Received Signal Strength Indicator)

A received signal strength indicator (RSSI) output is provided on this pin to aid in steering antennas and monitoring changes in relative signal strength of received signals.

Figure 2-4 is a graph plotting the typical RSSI voltage versus signal input. When measured with a DVM, the accuracy of the RSSI is approximately ± 10 dBm. The RSSI will be within 3 dBm when displayed on the HHT.

3.5 3

2.5 2

1.5

DC VOLTS

0.5 0

–140

–120

–100

–80

–60

–40

SIGNAL LEVEL (dBm)

Figure 2-4. Received Signal Strength Indicator Calibration Chart (Typical)

PIN 22: Loopback Test—Receive Audio Input

A direct input to the loopback and diagnostics module’s DTMF decoder. Can be used with external DTMF encoder to simulate a polling request from a master station. Nominal input signal level required: –10 dBm.

PIN 23: Open Diagnostics

A low on this input opens the diagnostics channel. If the terminal cable provides a ground for this pin the diagnostics channel automatically opens. If this pin is not grounded, the OPEN command is required from the HHT or terminal to allow diagnostics and control functions of the transceiver.

2-10 INSTALLATION MDS 05-2415A01, Rev. A

PIN 24: ETC—External Transmit Clock

This pin is used only on applications requiring a synchronous interface with an external device controlling the timing of the transmitted bits. The most common application of this pin is where the MDS 4310 is connected to an external high speed modem. In this case, a cross-over (“null-modem”) cable is required that connects Pin 17 (RC) from one modem to Pin 24 (ETC) of the other, and vice versa. In most instances, timing is controlled by the internal clock inside the MDS 4310 (from Pin 15), and Pin 24 should be left open. The External Transmit Clock signal is compatible only with RS-232 interfaces.

PIN 25: Out-of-Lock Alarm

A logic low (≤ 0.5 volts) on this pin indicates normal operation. A logic high (≥ 4 volts) indicates a failure in the main phase lock loop or TCXO, or a transmitter time-out condition. A logic high also causes the transmitter and receiver to be shut down. This pin can be used as an alarm output, if the internal series resistance of 1 kΩ is considered when designing an external interface circuit.

FRONT PANEL INDICATORS

The radio is supplied with a set of six light emitting diode indicators (LEDs) that provide information on the status of key operating functions. The indicators can be disabled if the jumper on the transceiver’s main board at J11, pins 2 & 2 is removed. With the pins bridged, the display is enabled. There are two versions of the plastic label for the front panel of the radio—one for radios without a modem installed (See Table 2-2), and one for radios with internal modems (See Table 2-3).

Table 2-2. External Indicators

PWR TX CD

RTS TXD RXD

LED FUNCTION INDICATES

PWR Power Indicator Primary power is applied and is greater than 10

TX Transmit The transmitter is keyed and is on-the-air CD Carrier Detect Receiver detects an on-channel signal and the

RTS Request To Send The RTU is asserting a Request To Send signal. TXD Transmit Data Reflects the current state of the Transmit Data

RXD Receive Data Reflects the current state of the Receive Data line

Vdc. If this indicator is flashing, the VCO is out-of-lock.

All transmit and receive functions are disabled.

squelch is open.

line from the Remote Terminal Unit (RTU). LED OFF=0, LED ON=1

from the transceiver internal modem. LED OFF=0, LED ON=1

MDS 05-2415A01, Rev. A INSTALLATION 2-11

TRANSCEIVER CONFIGURATION JUMPERS

The 4310 Transceiver has three jumper blocks that configure the transceiver. The following sections describe the use and function of these jumpers.

J11—TTL/RS-232 and LED Enable Jumpers

Jumper J11 configures two functions; the front panel LEDs and interface signal levels. See Figure 2-5 and Table 2-4 for jumper details.

With J11 Pins 1–2 jumpered, the

INTERFACE connector communications pulses are 0 or 5Vdc

and are commonly referred to as TTL. With no shunt across J11 Pins 1–2, U31 is enabled providing standard + and -12 Vdc signals on the RS-232 compatible signals available at the

INTERFACE connector. A shunt across J11 Pins 1–2 disables U31 which is the RS-232 line

driver/receiver IC. With U31 disabled, the signal lines are not converted to RS-232 12Vdc levels.

The function of J11 pins 3–4 allows the disabling of the LED indicators on the transceiver front panel. Disabling the LEDs allows less current consumption in solar-powered installations and other current sensitive installations. With J11 pins 3–4 jumpered the LED driver IC is enabled and the LEDs function. Conversely, when the jumper is removed from J11 pins 3–4 the LED driver IC is disabled and the LEDs do not function.

CAUTION

To prevent possible damage to the interface circuitry, disconnect primary power and the INTERFACE connector before changing jumpers. J11 Pins 1-2 must be shunted if any of the input/output lines are to be operated at TTL levels. Failure to do so can damage the transceiver or RTU or may cause intermittent operation.

PRINTED CIRCUIT

BOARD MODEL

LABEL

J16

FULL DUPLEX

INTERFACE

J14

RX AUDIO

NORMAL/INVERT

EXTERNAL

INTERFACE

J11

RS–232 DISABLE

LED ENABLE

341

1 2 3

TCXO

FREQUENCY

ADJUSTMENT

Figure 2-5. Location of Configuration Jumpers

2-12 INSTALLATION MDS 05-2415A01, Rev. A

Table 2-4. J11–External Interface TTL/RS-232

and Front Panel LED Configuration

LOCATION SHUNTED OPEN

1–2 TTL Enabled RS-232 Converter Enabled* 3–4 Front Panel LEDs Enabled* Front Panel LEDs Disabled

* Standard factory configuration

J14—Receiver Audio Output Phase

The receiver audio output phase can be shifted by 180 degrees (inverted) through the use of a programmable jumper on the transceiver’s motherboard at J14—Audio Normal/Inverted. The table below shows the possible positions of the jumpers. See Figure 2-5 for the board location of the jumper and Figure 2-6 for details. Do not move this jumper from its factory setting without first consulting MDS Systems Engineering.

Table 2-5. J14 Receiver Audio Output Normal/Inverted

LOCATION SHUNTED

1–2 Normal Audio* 2–3 Inverted Audio

* Standard factory configuration

J14

2 3

Figure 2-6. Detail of Configuration Jumpers—J14

J16—Full Duplex Option Connector

J16 Pins 1–2 and J16 Pins 3–4 must be jumpered for normal remote operation. The Full Duplex Option Connector is used only when the MDS 4310 is paired with another MDS 4310 transceiver for full duplex operation. Do not move these jumpers from the factory settings without first consulting MDS Systems Engineering.

MODEMS—GENERAL Introduction

MDS offers three modem interfaces for the MDS 4310 Data Transceiver operating at 1200, 4800 and 9600 bits per second. Details on each modem are provided in separate appendices at the end of this manual. Any one model of the modems can be installed in

MDS 05-2415A01, Rev. A INSTALLATION 2-13

the transceiver or in the MDS 4350/MDS 4355 packaged system, provided a complementary Interface/Utility board is installed in the MDS 4350/MDS 4355.

The following is a general discussion of modem interface signaling.

The Role of the Modem

The purpose of the modem is to convert RS-232 data passing through the external

INTERFACE connector into digital signals that will modulate the transmitter, and to convert

signals recovered from incoming radio signals into RS-232 data. The modem is also responsible for accepting RTS (Request To Send) from the INTERFACE connector and for acknowledging transmitter operation with a CTS (Clear To Send) signal through the

INTERFACE connector to the attached equipment.

RTS and CTS Signals

When RTS on the

INTERFACE connector goes high, the transmitter is keyed by the RTS

line connected to the modem. Whenever the transmitter is keyed, a timer is started that will, after a programmed time period, raise the CTS line at the INTERFACE connector. This CTS time delay allows time for the transceiver’s transmitter and the master’s modem circuitry to stabilize before data can be sent to the master station. CTS is programmable in 1 ms increments within the range of 5 to 255 ms. MDS recommends a minimum of 10 ms of CTS delay for optimum system performance. Thus, 10 ms is the factory default.

When RTS goes low, the transmitter is unkeyed and CTS is set to low.

DCD Signal

When the squelch circuit in the receiver senses the presence of a carrier, the DCD line goes high. When the squelch circuit in the receiver senses the lack of a carrier, the RXD output is forced to a “Mark” condition and the DCD signal is set low. RXD and DCD are signals on the

INTERFACE connector.

POWER REQUIREMENTS

The MDS 4310 Transceiver can be powered from any source with a nominal terminal voltage between 12 and 15 volts direct current and capable of supplying a minimum of 2.5 amperes.

NOTE

Under no circumstances should the nominal supply voltage drop below 10.5 volts or rise above 16.5 volts. The supply must be sufficiently regulated to limit any change in its output voltage to one volt or less when the transceiver alternates between transmit and receive.

The power output is factory adjusted for 5.0 watts at 13.8 volts. If the actual supply voltage is not 13.8 volts under load, the transceiver’s power output should be adjusted to 5.0 watts before the unit is put into service.

One approach to powering the MDS 4310 Transceiver from a 120 Vac source and providing for backup power during power outages is to float charge a 12 volt storage battery from a regulated 13.8 Vdc power supply. The radio can then be connected directly across the battery terminals. The power supply should be equipped with current limiting to protect it in the event the battery becomes deeply discharged during a long outage.

2-14 INSTALLATION MDS 05-2415A01, Rev. A

The battery used should be designed for deep discharge service. Such batteries are available from industrial battery distributors and retail outlets, where they are sold as power sources for recreational vehicles or for electric trolling motors for sport fishing.

ANTENNAS AND FEEDLINES Antenna Selection and Mounting

A directional Yagi or corner reflector antenna is required by the FCC for use on all remote stations to minimize interference to and from nearby systems. Good antennas of this type are available from a number of manufacturers. Some 450 MHz directional antennas are listed below.

Manufacturer Model Number

Antenna Specialists ----------- ASP-604 Sinclair-------------------------- SRL-307

SRL-307RC-HD

SRL-350 Telewave ----------------------- ANT450Y10 Scala ---------------------------- CA5-450

CA7-460

CL-400

RA5-450

The antenna manufacturer’s recommended mounting configuration for a particular antenna must be strictly followed. Use the proper mounting hardware and bracket to ensure a secure mounting arrangement with minimal pattern distortion. Any metallic object close to the antenna will distort the radiation pattern and, in severe cases, detune the antenna enough to cause a high VSWR on the antenna feedline.

CAUTION

Strong fields near the antenna can interfere with the operation of low level RTU circuits and change the reported values of the parameters being monitored. Also, objects in the near field of the antenna can increase VSWR and distort the antenna pattern, resulting in reduced system performance. The antenna should always be mounted at least 10 feet (≈3 meters) from the radio, RTU, sensors, and other components of the system.

When installing the antenna:

1. Mount the antenna in a clear space as far as possible from obstructions such as buildings, metal objects, foliage, etc. The importance of this matter cannot be overstated.

2. Make sure that the field is clear in the direction of the master station.

3. Orient the antenna in the direction of the master station if the direction is accurately known. Preferably, monitor the signal from the master station with a DC voltmeter connected to the radio’s RSSI pin (Pin 21 on the DB-25 connector), and rotate the antenna for maximum indication.

MDS 05-2415A01, Rev. A INSTALLATION 2-15

NOTE

A Yagi antenna can be oriented for either horizontal or vertical polarization. All systems using a gain type omni-directional antenna at the master station employ vertical polarization of the signal; therefore the remote antenna must also be vertically oriented, with its elements perpendicular to the earth’s surface. If the antenna is mounted with its elements parallel to the ground (horizontal polarization), the received signal strength can be reduced by 20 dB or more.

Feedline Selection

Choice of correct feedline (the coaxial cable that connects the radio to the antenna) for the particular circumstances of each installation is very important; poor cables can seriously degrade system performance and low loss cables, while superior, can be quite expensive.

For example, 100 feet (30.48 meters) of RG-58A/U cable (commonly used for low frequency operation) has an insertion loss of 13 dB at 450 MHz. A 5 watt transmitter operating into such a feedline would produce only 250 milliwatts at the antenna; a similar loss in receiver sensitivity would result and no amount of gain at the receiver can recover the signal lost in the feedline. On the other hand, a 100 foot (30.48 meters) length of 1 5/8 inch HELIAX has a loss of 0.55 dB at the same frequency, but its cost is many times greater than RG-58A/U.

In any point-to-multipoint system there will be a distribution of remote stations, with some closer to the master station than others. For the close-in units, feedline loss is not as important, and 6 dB or more of loss can be acceptable. For the furthest-out remote units, each decibel of loss directly affects bit error rate and the amount of time the system misses polls due to fading. Here, it is good practice to keep feedline losses well under 3 dB, with a target loss of only 1 dB.

NOTE

For each 3 dB of feedline loss, half the transmitter power is lost and twice the receiver signal is needed to produce the same bit error rate.

RG-8 or RG-214/U cable is widely available and inexpensive. It is suitable for close-in remote units or for those installations with short feedlines. For longer feedlines and lower losses, HELIAX® or similar cable is a good choice. Table 2-6 shows the maximum length of various types of cable that can be used to give 1, 3, 6 or 9 dB feedline loss.

Table 2-6. Signal Loss versus Cable Length and Type

CABLE TYPE

1 dB 3 dB 6 dB 9 dB

RG-8 18 (5.49) 54 (16.46) 109 (33.22) 163 (49.68) 1/2 inch Foam HELIAX 66 (20.12) 199 (60.66) 397 (121.01) 596 (181.66) 7/8 inch Foam HELIAX 120 (36.58) 260 (79.25) 719 (219.15) 1079 (328.88) 1-5/8 inch Foam HELIAX 194 (59.13) 582 (177.39) 1165 (355.09) 1747 (532.49)

LENGTH IN FEET (AND METERS)

TO PRODUCE INDICATED LOSS AT 450 MHz

2-16 INSTALLATION MDS 05-2415A01, Rev. A

Feedline Installation

It is absolutely essential that the feedline connectors be installed in accordance with the manufacturers’ instructions for the particular type of connector used. Also, any special tooling required for mounting the connectors must be used, to ensure maximum mechanical and electrical reliability. Be careful to check that the finished center pin dimensions are within specifications to prevent damage to mating connectors when the two are joined.

Connectors that are exposed to outdoor environments must be sealed to prevent moisture buildup in the connector. In extreme cases, rainwater can get into a connector and fill the entire feedline with water, creating a high loss cable that will have to be replaced. There are several good methods for weatherproofing these outside connections; consult the cable or connector manufacturer for their recommended materials and procedures.

The feedline itself must also be installed carefully to prevent short-term or long-term damage. Short-term damage can consist of kinking, twisting or excessive elongation of the cable during installation. Harmful long-term effects could be due to improper connector sealing, a bend that is too tight, insufficient strain relief on the cable when mounted on the tower, or excessive flexing and vibration due to wind.

MDS 05-2415A01, Rev. A INSTALLATION 2-17

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2-18 INSTALLATION MDS 05-2415A01, Rev. A

CHAPTER 3

PROGRAMMING AND DIAGNOSTICS

INTRODUCTION

A significant feature of the 4310 Transceiver is the ability to accomplish many radio programming and diagnostic tasks through software commands issued from a Hand-Held Terminal (HHT).

Software control of the transceiver allows measurement and adjustment without removing the top cover. In addition, when the Remote Maintenance feature is installed and enabled, many of the same programming and diagnostic functions can be accessed over the RF channel, thereby eliminating the need to travel to an installation site to perform minor checks and adjustments.

This chapter explains how to connect the HHT to the transceiver, open the Diagnostics Channel, and enter commands on the HHT keyboard. Step by step examples are used to support the programming and diagnostic instructions.

Table 3-2 includes a complete list of HHT commands. Experienced users may wish to refer directly to the table when programming or diagnosing the transceiver.

TERMINAL CONNECTION AND STARTUP

Connecting the HHT to the transceiver is simple, since the HHT interface cable includes a DB-25 adapter plug that allows direct connection to the radio’s INTERFACE connector.

NOTE

Before connecting the HHT to the transceiver, verify the radio is connected to a continuous +13.8 Vdc supply. (Most often the transceiver is powered continuously, but some solar-powered systems operate on an intermittent basis, making an alternate power source mandatory for testing.) MDS also recommends using a dummy load on the transceiver during all testing. This prevents accidental interference to the rest of the radio system.

To connect and startup the HHT, follow these steps:

1. Remove the RTU interface cable from the and set it aside. This step is not required for the MDS 4355 packaged system.

2. Plug the HHT into the INTERFACE connector as shown in Figure 3-1. If it is a MDS 4355 packaged system, plug the HHT into J3 of the Interface/Utility assembly as shown in Figure 3-2.

3. Press and hold the heard from the HHT, then release the

ENTER

key as the HHT runs through its self-check, a click will be

ANTENNA connector of the

INTERFACE connector on the transceiver

ENTER

key.

MDS 05-2415A01, Rev. A 3-1

4. This completes the HHT startup procedure. After a five second “quiet time” (no reception of radio signals), the Diagnostics Channel may be opened as outlined below.

INTERFACE

TR MR CD

ANTENNA

13.8 VDC

TD IN RD

(

–

)

CTRL

●

ENTER

SPACE

ESC

BKSP

SHIFT

–

Figure 3-1. Hand-Held Terminal Connected to the MDS 4310 Transceiver

SW1

R28

TB2TB1

CR7

R10

TB2

RS-232

INTERFACE

Figure 3-2. MDS 4355 Packaged Transceiver

3-2 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

Special Instructions for Radios Configured as TTL

In most cases, an HHT can be plugged directly into the radio’s INTERFACE connector and used immediately. However, in some cases, the INTERFACE connector may have been configured for TTL operation (as opposed to the more common RS-232 format) using the radio’s J11 jumper.

If you are unsure of which configuration you have, look at J11 on the transceiver’s motherboard. In an RS-232 radio, J11 pins 1-2 will be empty (open).

If your radio is configured for TTL, an optional TTL to RS-232 adapter plug is available from MDS (P/N 03-2223A01) to allow connection of the HHT or other RS-232 equipment, making the transceiver appear as an RS-232 device. Contact MDS for ordering information.

If the TTL to RS-232 adapter plug is not available, it is also possible to temporarily reconfigure the INTERFACE connector for RS-232 operation by removing the jumper on J11 pins 1–2. (See Table 2-4 for proper jumper placement.) When testing is complete, J11 can be restored to its TTL configuration.

Plugging an HHT or a PC into a transceiver configured for TTL signaling will key the radio transmitter, and will not allow terminal operation. However, no damage will be done to the terminal or radio.

Opening The Diagnostic Channel

NOTE

The diagnostic channel between the HHT and the transceiver is automatically opened when a HHT is connected to the transceiver. However, if an older HHT or transceiver is being used, it must be opened before HHT functions can be performed. To manually open the diagnostic channel when using older HHTs or transceivers, follow the steps below:

1. After the HHT has completed its self-check, look for a solid flashing cursor on its display. This indicates that the Diagnostic Channel is closed and that the HHT is ready to accept the

OPEN command.

2. Press ENTER . Wait at least five seconds to satisfy the required “quiet time.”

3. After the five second quiet time, type

4. When the channel opens, the message "

OPEN + ENTER .

DIAGNOSTICS IS OPEN" appears.

NOTE

If the Diagnostics Channel does not open the first time, wait at least 5 seconds before trying again.

When the Diagnostics Channel is open, any keyboard entry is echoed by the transceiver and appears on the HHT display. In radios that have a modem installed, the received data (RD) and the transmit data (TD) LEDs will flash to indicate the exchange of information between the HHT and the radio’s microcontroller.

The radio’s microcontroller and the modem share the communications lines connected to the

INTERFACE connector. In this way, no data will be passed through the modem to the

transmitted signal when the INTERFACE connector is connected to the HHT and the diagnostics channel is open.

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-3

CAPABILITIES OF THE HHT

With the HHT properly connected to the transceiver’s DB-25 INTERFACE connector, the following can be performed.

• Review operating parameters and diagnostic information

• Set the operating parameters of the radio

• Program user information

All of these tasks can be performed with the radio mounted in its final operating position without the need for removing the top cover of the transceiver enclosure.

Review Operating Parameters and Diagnostic Information

The user can review the current settings of various operating parameters of the radio, as well as monitor several key test points in the radio. These parameters include:

• Radio model number, serial number and date of manufacture

• Transmit and Receive Frequencies

• Supply voltage, Lock voltage and Regulator voltage

• Transmit Forward Power Output

• Antenna Voltage Standing Wave Ratio—VSWR

• Time-out Timer Length

• Squelch Tail Eliminator Status*

• RTS/CTS Delay Interval

• Soft Carrier Dekey**

• Push-To-Talk Delay

• Temperature Inside Radio Housing

The values of diagnostic parameters (voltages, signal strength, etc.) are updated once every second to allow the technician to make adjustments while observing the HHT display. In this way, you do not need to invoke the diagnostic command each time a control is moved.

* The Squelch Tail Eliminator circuit senses the end of the incoming data message (by

detecting the loss of the 1200 Hz mark/idle tone), and shutting off the receiver’s audio before the received carrier drops. In this way, the receiver does not misinterpret the squelch tail noise burst as data. The Squelch Tail Eliminator feature is only available on analog radios.

** The Soft Carrier Dekey feature keeps the transmitter keyed for a short period

(typically 4 ms or less) after the RTU has sent the last data bit to the transceiver. This allows the modem time to process and transmit all of the characters in each message, and reduces the possibility of framing or BCH (cyclic frames) errors.

† Push-to-Talk delay inserts a programmed delay (typically 5 to 31 ms) between the

time the RTS or PTT line is asserted and when the transmitter is actuated. This is done to prevent carrier overlap (two stations transmitting at once) and other timing problems that could otherwise occur in some systems, especially those with repeaters. Carrier overlap causes lost or corrupted data.

†

3-4 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

Setting the Operating Parameters

The user can select and set several of the operating parameters of the radio. These parameters include:

• Transmit Frequency

• Receive Frequency

• Time-out Timer Length

• Enable or Disable Time-out Timer

• Squelch Tail Eliminator Status

• RTS/CTS Delay Interval

• Soft Carrier Dekey Delay Length

• Loopback Code

• Push-To-Talk Delay

Program User Information

The user can program information into the radio that is specific to the individual user. This information includes:

• Owner’s Name (20 characters total)

• Owner’s Specific Message (For example—assigned location or date unit placed in service. 27 characters total).

This information is stored in EEPROM, and will remain programmed in the radio until new information is entered.

USING THE HAND-HELD TERMINAL—Basic Operations Command Syntax

The proper procedure for using the review commands is the command, followed by an keystroke. For the programming commands, the appropriate command is followed by a keystroke, followed by the information or values, then

ENTER

. See Programming Examples

ENTER

SPACE

for further information.

Shift Key

The shift key is used to access the numbers on the keyboard of the HHT. Pressing the key once locks the keyboard into the upper level character set; the

SHIFT

key has to be

pressed again to return to the main character (alphabet) set. Exception: Pressing the

SHIFT

ENTER

key automatically returns the keyboard to the main character set.

Backspace (BKSP) Key

BKSP

The Backspace key entered with the keyboard. The backspace key works only when the

can be used to edit information or commands as they are being

SHIFT

key has the

alphabet selected.

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-5

Error Messages

Listed below are common error messages that may be encountered when using the HHT.

INCORRECT ENTRY"

Data was entered in a wrong format, or wrong number of digits.

"COMMAND ENTRY ERROR"

Command improperly entered, or an invalid command was tried.

"INCORRECT FREQUENCY ENTRY"

Last digit of frequency was omitted, or frequency entered was out of range.

"DIAGNOSTICS NOT INSTALLED"

Diagnostic Board not installed or not detected by radio’s microcontroller.

Closing the Diagnostic Channel

The diagnostic channel between the HHT and the transceiver is automatically closed when a HHT is disconnected to the transceiver. However, if an older HHT or transceiver is being used, it must be closed before returning the transceiver to service. To manually close the diagnostic channel when using older HHTs or transceivers, type in CLOS +

ENTER

. The message "DIAGNOSTICS IS CLOSED" will be displayed, indicating a closed condition. At this point it will be noticed that either the running cursor or the stationary solid flashing cursor returns, and that all further keystrokes will be ignored by the HHT, another indication that the diagnostics channel is closed.

BKSP

●

ESC

SPACE

ENTER

(

)

–

CTRL

SHIFT

Figure 3-2. Hand-Held Terminal Keypad

NOTE

The Diagnostics Channel automatically closes after 15 minutes of no keyboard activity. If this happens, simply re-open the channel to resume transceiver testing.

PROGRAMMING EXAMPLES

Refer to Figure 3-2 or an actual HHT for the following discussion. The following is an example of reprograming the MDS 4310 Transceiver in the field, using the HHT. The current parameters of operation are:

• Transmit frequency = 428.0125 MHz

• Receive frequency = 438.0125 MHz

3-6 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

• Time-Out Timer length = 30 sec

• Soft Carrier Dekey = 0 ms

• Squelch Tail Eliminator = On

The transceiver is to be programmed to operate in a system requiring the following parameters:

• Transmit frequency = 428.8375 MHz

• Receive frequency = 438.8375 MHz

• Time-Out Timer length = 94 sec

• Soft Carrier Dekey = 4 ms

• Squelch Tail Eliminator = off

• Loopback Code = 1234

The list of steps and commands below will program the MDS 4310 with the required values.

1. Connect the HHT to the transceiver as previously outlined, and open the diagnostics channel if necessary.

2. Verify the current frequencies by typing

TX FRQ = 428.01250 RX FRQ = 438.01250

FRQ +

ENTER

. Display will read:

3. Program the new transmit frequency by typing PTX +

428.83750 +

The display will read

SHIFT + ENTER

TX FRQ PRGMD TO 428.83750 MHZ if the information was entered

. Be sure to include the decimal point and all trailing zeros.

SPACE + SHIFT

correctly and accepted by the microcontroller.

4. Program the new receive frequency by typing

438.83750 +

SHIFT + ENTER

, again taking care to enter in all characters.

PRX +

SPACE + SHIFT

If the information was entered properly, and accepted by the microcontroller, the display will read

5. Program the time-out timer length by entering + 94 +

SHIFT + ENTER

6. Program the soft carrier time by entering

SHIFT + ENTER

7. Disable the STE by typing

ELIMINATOR OFF

8. The information entered in can now be reviewed by using the

RX FRQ PRGMD TO 438.83750 MHZ.

PTOT +

SPACE + SHIFT

. The display will read TIME-OUT TIMER SET TO 094 SECS.

PSCD +

. Display will read SOFT CARR. DEKEY SET TO 004 MS.

DSTE +

ENTER

. The display will read SQUELCH TAIL

SPACE + SHIFT

+ 4

FRQ, TOT, SCD and STE

commands to review each setting.

9. Enter the loopback code by typing

ENTER

. The display will change and read LOOPBACK CODE = 1234.

PLBC +

SPACE + SHIFT

+ 1234 +

SHIFT

10. Close the diagnostics channel by typing

CLOS +

ENTER

before unplugging the HHT.

This completes the programming sequence.

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-7

PROGRAMMING OWNER’S INFORMATION

The information accessible by the OWM and OWN commands can be programmed by the user to allow information unique to the radio transceiver or its location to be stored in the EEPROM. Normally, this field is left blank on units as shipped from MDS.

To program these fields, proceed according to the following directions:

1. Open the diagnostics channel.

2. Type in

POWN +

SPACE

, followed by the owners’ name, etc. This is limited to a

maximum of 20 characters. When the desired information has been entered, press

ENTER

. The display will read INFORMATION PROGRAMMED.

3. Type POWM + of 27 characters. When the desired information has been entered, press

SPACE

, followed by the desired message, not to exceed the maximum

ENTER

. The

display will read INFORMATION PROGRAMMED.

4. Review the information by typing

OWN or OWM to verify that the desired message has

been entered. If either message has an error in it, the information will have to be reentered using the above steps.

5. Close the diagnostics channel.

PASSWORD PROTECTION

If password protection of programmed information (frequency, owner’s name and message, etc.) is used, the PASS command followed by the correct four-character password must be entered before the transceiver programming can be changed. Without the proper password, the programmed information and diagnostic data can only be reviewed, and no access to the programming commands is possible.

For more information on password protection, contact the MDS Systems Engineering.

DIAGNOSTIC EVALUATION

Using the diagnostic commands, a technician can read important voltages and levels with the HHT. These values are updated once every second, allowing adjustment of the levels without the need for invoking the command each time a control is moved. Below is a list of the commands, with the display to be expected after typing the command followed by an

ENTER

keystroke.

SV ------------- Supply voltage supplied to transceiver.

Display will read SUPPLY VOLTAGE = xx.x VOLTS.

VR ------------- Main regulator voltage.

Display will read +8V = xx.x VOLTS.

RSSI ---------- Received signal strength at ANTENNA connector.

Display will read RSSI = –xxx DBM.

LV ------------- PLL VCO lock voltage.

Display will read LOCK VOLTAGE = xx.x VOLTS IL.

NOTE

The

IL is an in-lock indicator; if the PLL is

out-of-lock, the display will show OL.

3-8 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

With the radio’s transmitter keyed…

FPWR ---------- Forward RF power output of Transceiver.

Display will read FWD POWER = xxx WATTS.

VSWR ---------- Calculated VSWR based on forward and reflected power levels.

Display will read VSWR= x .x : x.

Test Modes

Using the Hand-Held Terminal, a technician can invoke several diagnostic and test modes that are useful in evaluating the operation of both the transceiver and an internal modem. The test modes are invoked by typing the commands listed below followed by an

ENTER

keystroke.

KEY ----- Keys the transmitter with the transmit modulation enabled. DKEY---- Unkeys the transmitter. TEST_1-- Keys the transmitter and enables a constant DTMF Loopback test tone. This

test is useful for measuring the radio’s diagnostic deviation level with a communications monitor.

TEST_2-- Disables the DTMF Loopback test tone and unkeys the transmitter. TEST_5-- Disables the transceiver’s VCO circuit. TEST_6-- Enables the transceiver’s VCO circuit. TEST_7-- Turns on the modem test tones and keys the transmitter for 12 seconds.

• With 1200 bps modem: 1200/2200 Hz tone.

• With 4800/9600 bps modem: Sine wave at 1/2 data rate (bps).

EQUIPMENT DIAGNOSTICS DEFINITIONS

Software is available for service personnel to use a MDS Master Station as a diagnostics tool for system monitoring and maintenance. MDS 2000 Diagnostic and Control System software uses the master station to transmit a special message to all remote radios in a given system asking one remote radio at a time to respond with a test signal. The test signal is analyzed by the master station and the results are displayed on the screen of a personal computer running the MDS software. In order for the software to know which radios to poll for a test signal, an “Equipment List” must be created by the system operator which describes the address of the radio and its capabilities. The remote radio’s diagnostic address is referred to as its loopback code in MDS documentation and software. For more information, refer to the MDS 2000 Diagnostics and Control System Software User’s Guide (MDS P/N 05-1919A01).

Since it is possible to have MDS 4310 radios of different capabilities installed in the same system it is very important to know the exact profiles of each unit. The following are descriptions of the various diagnostic capabilities available for the MDS 4310 Transceiver.

All of the diagnostic modes listed in Table 3-1 are available from MDS 4310 transceivers with a Remote Maintenance Module (P/N 03-1958A01) properly installed in jacks J5 and J7 of the transceiver motherboard.

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-9

DIAGNOSTIC EXAMPLES RF Power Output Check

Suppose you wish to read the transmitter output power while the HHT is connected. The following steps will accomplish this.

1. Connect the transceiver to a dummy load.

2. Type

KEY +

ENTER

, to key the transmitter.

3. Type

FPWR +

ENTER

, to display the forward power output level.

4. As a further performance check, the DC voltage supplied to the transmitter can be

ENTER

read by typing

SV +

5. Unkey the transmitter by typing

DKEY +

ENTER

Received Signal Strength Indication (RSSI) Check

To invoke the RSSI function, simply type the signal level at the

ANTENNA connector in dBm. The display is updated once every second.

RSSI +

ENTER

on the HHT. The display indicates

This check can be especially useful when aiming the antenna at the remote site for maximum signal level. By using the RSSI command and the continuously updated display, an installer can aim the antenna in the direction of maximum field strength.

Table 3-1. Diagnostic and Control Capabilities

LEVEL MODE DESCRIPTION

Loopback 1 A radio set to Mode 1 diagnostics will respond to a poll containing a four-digit

Advanced 2 With a radio set to Mode 2, critical diagnostic information available through a

number string called the “Loopback Code.” When the remote radio decodes its loopback code transmitted by an MDS master station, it responds by keying its transmitter for several seconds with a continuous modulating tone. The radio’s signal strength and deviation can then be measured by the Master Station.

local HHT or personal computer is available over the RF channel to the Master Station. This includes: transmitter RF power output, the primary power supply voltage, the internal +8 Vdc regulated voltage level, the synthesizer’s lock voltage and the radio’s internal temperature. In addition, the diagnostic analysis of the remote unit’s signal, as received by the Master Station receiver will be displayed on a personal computer connected to the master station. These values include received signal level, carrier frequency offset (error) and modulation level/deviation.

Remote Maintenance

3 This is the highest level of diagnostics and control capability available for the

MDS 4310 transceiver. With Remote Maintenance enabled, all of the above diagnostic capabilities are available and, in addition, many of the radio’s parameters can be adjusted either locally with an HHT or over the RF channel with a personal computer running MDS 2000 Diagnostic and Control System software. Since it provides the greatest level of diagnostics and control, many users prefer to keep the transceiver set to Mode 3 diagnostics.

3-10 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

PROGRAMMING AND TEST COMMANDS

Table 3-2 contains a list of all HHT programming and diagnostics commands.

NOTE

Some command strings in Table 3-2 include an underscore “_” symbol to denote a

SPACE key press. The underscore is a visual

reminder only, and should not be entered.

Table 3-2. Programming and Test Commands—Part 1 of 3

DIAGNOSTICS CHANNEL

OPEN... OPEN the Diagnostics Channel CLOS... CLOSE the Diagnostics Channel

DISPLAY COMMANDS

HARDWARE STATUS

STAT.... Display status of hardware profile

Displayed below are the functions of each display character and its meaning.

1 Keyed Status................ U – Unkeyed

K – Keyed T – Timed Out

2 Diagnostic Mode .......... S – Standard (Mode 1)

A – Advanced (Mode 2) R – Remote Maint. (Mode 3)

3 Diagnostic Hardware ... A – Installed, LBC Valid

B – Installed, LBC Invalid C – Uninstalled, LBC Valid D – Uninstalled, LBC Invalid

OWNER’S INFORMATION

OWM.... Display Owner’s Message OWN.... Display Owner’s Name

RADIO INFORMATION

HREV ... Transceiver hardware revision level

MD........ Transceiver manufacture date

MO ....... Model number of radio

OPERATING PARAMETERS

CTS...... Displays CTS delay in ms

FRQ ..... Frequencies currently set in MHz

LBC...... Display Loopback code (4 digits)

SCD Display Soft Carrier Dekey in ms

DIAGNOSTIC INFORMATION

FPWR .. Forward RF power*

LV ........ PLL VCO lock voltage

RPWR.. Reverse RF power*

RSSI .... Received Signal Strength Indicator*

4 Diagnostic Module ....... I – Installed

U – Uninstalled5

Base/Remote .............. B – Base (High Side LO)

R – Remote (Low Side LO)

6 IF/LO Arrangement ..... 0 – 45 MHz/Low

7 RSSI Cal. Status.......... Y – Calibrated

N – Uncalibrated

8 RF Power Status.......... Y – Calibrated

N – Uncalibrated

SER...... Serial number of radio

SREV... Transceiver firmware revision level

PTT ...... Display Push-to-Talk delay in ms

STE...... Display Squelch Tail Eliminator (STE)

Status— ON or OFF (Normally OFF if VOX function is used.)

TOT...... Display Time-out Timer length (sec)

SV........ Supply voltage to radio*

TEMP... Internal temperature in degrees Celsius*

VR........ Regulator voltage output ≈8 Vdc*

VSWR.. VSWR at ANTENNA connector*

* Information is updated every second

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-11

Table 3-2. Programming and Test Commands—Part 2 of 3

DIAGNOSTIC AND TEST MODES

TEST MODES

KEY ......... Keys the transmitter

DKEY....... Dekeys the transmitter

TEST_1 ... Keys the transmitter and enables a constant

TEST_2 ... Disables DTMF Loopback test tone and

(Transmit modulation enabled)

DTMF Loopback test tone. Useful for checking the radio’s

diagnostic

unkeys the transmitter.

deviation level

TEST_5.... Disables VCO

TEST_6.... Enables VCO

TEST_7.... Turns on modem test tones and keys the

transmitter for 12 seconds.

• With 4800/9600 bps modem: Sinewave at 1/2 data rate.

• With 1200 bps modem: 1200/2200 Hz tone.

DIAGNOSTIC MODES

MODE_1 .......... Enable-Standard Diagnostics

MODE_2 .......... Enable-Advanced Diagnostics

MODE_3_xxxx . Enable Remote Maintenance

Functions (xxxx is the data rate in bps)

NOTES– Remote Maintenance Module (03-1958A01)

must be installed to invoke these functions. 4-wire radios in Mode 3 must use 1200 as the

modem data rate.

DIAGNOSTIC CALIBRATION

These commands are used with calibrated test equipment attached to radio. CPWR. Calibrate forward power to 5 Watts for diagnostics

RSSL... Calibrate RSSI at –110 dBm

RSSH... Calibrate RSSI at –70 dBm

SET/PROGRAM COMMANDS

OPERATING PARAMETERS

PASS_xxxx ...... Password Entry

PTX_xxx.xxxx... Program transmit frequency† PRX_xxx.xxxx .. Program receive frequency†

PLBC_xxxx....... Program loopback code (0000–9999)

ESTE................ Enable Squelch Tail Eliminator

PCTS_xxx ....... Program CTS Delay in ms; 2-255 ms, no

leading zeros (1–3 digits)

† A move of more than 6 MHz requires re-alignment of the transceiver’s tuned circuits. Consult factory for details.

POWER, FREQUENCY AND DEVIATION

PSCD_xxx ....... Program soft carrier dekey; 2–255 ms,

no leading zeros (1–3 digits)

ETOT .............. Enable Time-out Timer

DTOT .............. Disable Time-out Timer

PTOT_xxx........ Program Time-out timer (sec)

(1–3 digits)

PPTT_xx .......... Program Push-to-talk delay (0-31 ms)

A Remote Maintenance Module (P/N 03-1958A01) must be installed in the transceiver and the transceiver must be set to Mode 3 Diagnostic for these commands to have any effect. Electronic controls (EEPOTs) for these parameters are incremented or decremented as a percentage of their maximum value—zero to 100 percent. Changes in these settings are not permanent until the RMST command is sent.

GENERAL:

RMRD .............. Read present EEPOT settings

RMIST .............. Store present EEPOT settings

RMIS ................ Reset all EEPOTs to 50% and store

settings

RMOV .............. Restore all EEPOT to the previously

stored settings to 50%.

<SPACE> ........ Repeat last adjustment command

FREQUENCY:

IF ...................... Increment Frequency by 1

DF .................... Decrement Frequency by 1

INCF_xx ........... Increment Frequency by xx value

DECF_xx .......... Decrement Frequency by xx value

PRIMARY MODULATION:

ID ..................... Increment Deviation by 1

DD.................... Decrement Deviation by 1

INCD_xx........... Increment Deviation by xx value

DECD_xx ......... Decrement Deviation by xx value

POWER:

IP ..................... Increment Power by 1

DP .................... Decrement Power by 1

INCP_xx........... Increment Power by xx value

DECP_xx ......... Decrement Power by xx value

OWNER’S INFORMATION

POWN_xxxxx....... Program owner’s name

(20 characters maximum)

POWM_xxxxx....... Program owner’s message

(27 characters maximum)

3-12 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

Table 3-2. Programming and Test Commands—Part 3 of 3

REMINDERS

• All command entries end with the ENTER key.

• Use the SHIFT key to access numbers; press again to return to characters.

• Square cursor ( ) – letter mode is selected.

• Rectangular cursor ( ) – number mode is selected.

• Use ESC/BKSP key to edit information or commands being typed in.

• An underlined blank space (xx_xx) on command list indicates a required space.

HAND-HELD TERMINAL SETUP DEFAULTS

Occasionally, users of the HHT will key in a sequence of characters that will alter the internal microcontroller operating defaults and cause it to no longer be able to exchange data with the radio. The following is a set of instructions for reinitializing the HHT for use with MDS radio products.

Restoring the HHT Operation Defaults

1. Plug the HHT into the radio and apply power to the radio. A small rectangular cursor will appear on the display.

2. Put the HHT into the Setup Mode by pressing the following keys in sequence: SHIFT + CTRL + SPACE . The HHT responds with a screen display similar to that shown in Figure 3-3.

AF1B

Figure 3-3. HHT Initialization Display

Reviewing and Changing Defaults

1. The first of 15 menu items will be displayed. See Table 3-3. All of the items can be reviewed by pressing the “NEXT” function controlled by the

E key. The menu

parameter setting can be changed by pressing the “ROLL” function controlled by the A key.

2. Set up the HHT as listed in Table 3-3.

3. To “EXIT” the setup mode, press

C for “EXIT”, or it will automatically be closed

after the final item on the setup menu has been reviewed and the “ROLL” function is selected.

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-13

Table 3-3. Hand-Held Terminal Operating Defaults

PARAMETER SETTING

Re-init HT NO Baud Rate 1200 Comm bits 8,1, n Parity Error OFF Key Repeat OFF Echo OFF Shift Keys YES Ctl Chars PROCS Scroll on 33rd Cursor ON CRLF for CR ON Self Test SLOW Key Beep ON Screen size 32 Menu Mode LONG

HAND-HELD TERMINAL WIRING

The HHT is a very reliable unit, but the 6-conductor coiled cord or its RJ-11-6 modular connectors can be damaged by over-stretching or being dropped. The coiled cord is wired as a straight pin-for-pin assembly and the parts required to construct a replacement cable can be obtained from many electronics supply companies. Although similar in appearance, the cable set is not the same as an RJ-11-4 (4-conductor) telephone coiled cord.

Adapter Plug Wiring

Figure 3-4 shows the internal wiring of the DB-25 interface adapter plug that is used to connect the HHT to the transceiver.

DB-25RJ-11-6

1 2 3 4 5 6

N/C

3 2 7

Figure 3-4. DB-25 Interface Adapter Wiring

HHT ALTERNATIVES

As an alternative to using the HHT, a PC running terminal software (such as PCPLUS™, PROCOMM™, etc.) can be used to program the transceiver. Also, any ASCII terminal

3-14 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

supporting a standard RS-232 interface can be used. The software commands for PC or ASCII terminal control are identical to those listed for the HHT. (See Table 3-2.)

The communications settings for a PC or ASCII terminal must be as follows:

• Bit rate = 1200 bps.

• Number of data bits = 8, 1 stop bit

• No parity

• Full duplex mode

• Caps Lock enabled

Cable Wiring for a PC or ASCII Terminal

CAUTION

When connecting a PC or ASCII terminal to the MDS 4310 Transceiver, use only the required pins specified below. Do

not use a straight DB-25 to DB-25 cable wired pin for pin.

The use of improper cables may cause equipment damage.

The cable connecting the PC or terminal to the transceiver must connect the TXD, RXD, DSR and signal ground pins (DB-25 INTERFACE connector pins 2, 3, 6 and 7) as shown in Figures 3-5 and 3-6. Pin 23 can be be connected to ground to automatically open the diagnostic channel. If the PC or terminal is to be used for purposes other than diagnostics or programming, do not connect Pin 23.

NOTE

A transceiver equipped with an internal modem can transmit when connected to a PC, because of activation of RTS. Ensure that the

ANTENNA connector has a 50 ohm termination on it

before proceeding.

COMPUTER DB-9

TXD

RXD

RTS

CTS

GND*

DCD

FEMALE MAL

* Signal Ground

RADIO DB-25

TXD

RXD

OPEN

GND*

DSR

Figure 3-5. DB-9 to DB-25 Interface Cable Wiring

COMPUTER DB-25 RADIO DB-25

TXD

RXD

RTS

CTS

GND*

DCD

FEMALE MALE

* Signal Ground

TXD

RXD

OPEN

GND*

DSR

Figure 3-6. DB-25 to DB-25 Interface Cable Wiring

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-15

This page intentionally left blank.

3-16 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

CHAPTER 4

FIELD TESTS AND ADJUSTMENTS

DANGER

The MDS 4310-HL data transceiver is approved for use in Class I, Groups ABCD, Division 2, Hazardous Locations. The installer of these transceivers MUST be familiar with hazardous location installation guidelines before any installation or maintenance is begun. Do not begin installation of or make external connections to this device unless the area is known to be non-hazardous.

Refer to Appendix H of this manual for further information on the approved conditions under which the MDS 4310-HL can be installed in hazardous locations.

GENERAL

This chapter describes field tests and adjustments that can be used to diagnose suspected problems or evaluate the transceiver after an assembly has been replaced. These tests are not

normally required for new installations (with the exception of checking the supply voltage to the radio and testing antenna system performance). Unless otherwise noted, the

procedures given here apply equally to the MDS 4310 transceiver and the MDS 4350/4355 packaged models. For additional set-up information on the MDS 4350 and MDS 4355, refer to Appendices F and G respectively.

NOTE

All units are tuned at the factory for optimum performance. Do not re-tune any unit without first checking the performance as it is. Retuning may not be necessary.

TEST EQUIPMENT REQUIRED

Directional RF Wattmeter—It must be equipped with a plug-in element rated for 10 watts

and 1,000 MHz. A popular directional wattmeter suitable for this service is the Bird Model 43 Thruline™ wattmeter with the Bird 10D element.

Service Monitor— This is an instrument that performs the combined functions of RF

and audio signal generator, frequency meter/counter, modulation analyzer and RF watt–meter. Monitors are typically equipped with an input attenuator/dummy load that allows the full output of the transmitter to be safely coupled directly to the instrument. If this last feature is not provided, you will need a separate attenuator/dummy load. Suitable service monitors are manufactured by the IFR Division of Regency, Inc., Marconi Instruments Ltd., and Hewlett Packard. It is also possible to use separate test equipment in place of a service monitor, but this may be impractical for field work.

Continued on next page.

MDS 05-2415A01, Rev. A 4-1

TEST EQUIPMENT REQUIRED Continued

Frequency measuring equipment usually requires a “warm-up” period to achieve maximum accuracy; a warm-up period of 30 minutes is not uncommon. Please read the unit’s instruction manual before proceeding with frequency measurements.

NOTE

FCC regulations require a frequency accuracy of .00015% (1.5 ppm). MDS transceivers meet this requirement by using temperature compensated crystal oscillators. A frequency counter used to set the transceiver on-frequency must have an accuracy that is five to ten times better than what it is reading, which is an accuracy of .00003% to .000015% (0.3 to 0.15 ppm).

If a frequency counter with a frequency accuracy of better than 0.3 ppm is not available, do not make any adjustments to the transceiver frequencies.

DC Voltmeter—A digital voltmeter such as a Fluke 75 is suitable. Oscilloscope—If the service monitor does not contain a low frequency oscilloscope, then

a basic one is required. The oscilloscope should have a frequency response of 100 kHz or higher, AC/DC coupling and have a horizontal sweep resolution of 2 ms per division.

MDS Hand-Held Terminal (HHT)—Kit P/N 02-1501A01. The HHT is most

convenient way to set the operating parameters controlled by the transceiver’s microcontroller, and to use the built-in test and diagnostic features of the radio.

NOTE

To perform the tests in this chapter, operators must be familiar with connecting the HHT, opening and closing the Diagnostics Channel and issuing the required commands. Chapter 3— Programming and Diagnostics contains complete instructions for using the HHT.

If desired, a personal computer running a standard terminal emulation program such as PCPLUS™ or PROCOMM™ can be substituted for the HHT. In this case, the program should be set to 1200 bps, eight data bits, no parity, and one stop bit. The keyboard must be set with the

caps lock

key pressed; the radio responds only to commands and numbers entered in uppercase characters. The commands for a PC are identical to those used with the HHT. (See Chapter 3—Programming and Diagnostics, for more information.)

Room Thermometer—This thermometer should be accurate to 1°C. It is used to

calibrate the temperature sensor on the Remote Maintenance Module.

Power Supply—The output needs to provide 12–14 Vdc at 3 amperes or more. Small, flat-bladed adjustment tool—It is used to adjust potentiometers on the

transceiver. It should be made of plastic or metal.

Data Terminal Emulator—This device is required for radios with a built-in modem

installed. It is used to key the transceiver and simulate incoming data on the DB-25

INTERFACE connector. A simple terminal emulator can be wired for this purpose as

4-2 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

shown in Figure 4-1. The transceiver’s INTERFACE connector must be configured for RS-232 operation for proper operation of the emulator. (See “Special Instructions for Radios Configured as TTL” below if your radio has been configured for TTL.)

NOTE

As an alternative to a Data Terminal Emulator, a “breakout box” or jumpers can be attached to the transceiver’s

INTERFACE

connector and configured with the proper connections as shown in Figure 4-1.

Special Instructions for Radios Configured as TTL

In most cases, a data terminal emulator can be plugged directly into the radio’s INTERFACE connector and used immediately. However, in some cases, the INTERFACE connector may have been previously configured for TTL operation (as opposed to the more common RS-232 format) using the radio’s J11 jumper field.

If you are unsure of which configuration you have, look at J11 on the transceiver’s motherboard. In an RS-232 radio, all pins on J11 will be empty (open), with the possible exception of a jumper on Pins 13 and 14 (LEDs enabled). By contrast, a TTL radio will have jumpers installed on pins of J11, with the possible exception of Pins 13 and 14.

If your radio is configured for TTL, an optional TTL to RS-232 adapter plug is available from MDS (P/N 03-2223A01) to allow connection of the Data Terminal Emulator, an HHT or other RS-232 equipment. This unit plugs between the transceiver’s INTERFACE connector and the external equipment, making the transceiver appear as an RS-232 device. Contact the factory for ordering information.

If the TTL to RS-232 adapter plug is not available, it is also possible to temporarily reconfigure the INTERFACE connector for RS-232 operation by removing the jumpers on J11. (See Table 2-4 for proper jumper placement.) When testing is complete, J11 can be restored to its TTL configuration.

all

CONSTRUCTING A DATA TERMINAL EMULATOR Introduction

The right side of Figure 4-1 shows the proper wiring for a simple data terminal emulator. There are two ways to construct the Data Terminal Emulator; both techniques are electrically identical and use common parts available from most electronic parts supply stores. The difference is in the packaging of the two units.

Emulator Design #1

Method 1 requires two small toggle switches (SW1 & SW2), and a DB-25 male connector with a cover that is large enough to mount the toggle switches inside it. (See the top part of Figure 4-2.)

Emulator Design #2

Method 2 requires two toggle switches (SW1 & SW2), a DB-25 male connector, a short length of three-conductor cable, and a small enclosure. (See the lower part of Figure 4-2.)

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-3

RADIO

TRANSCEIVER

+5 VDC

RTS DSR

1 K

TXD

Transceiver

Interface

Connector

Pin 4

Pin 6

Pin 2

Male DB-25 Connector

TERMINAL

EMULATOR

STANDBY

XMTR KEYED

SW1

SW2

SPACE MARK

Figure 4-1. Remote Data Terminal Emulator Wiring

SW1 and SW2 mounted inside a small enclosure

SW2

(TXD)

SW1

(RTS)

METHOD ONE

SMALL TOGGLE

SWITCHES

(SPST)

SMALL ENCLOSURE

(Plastic or Metal)

3 CONDUCTOR

SW1

(RTS)

SW2

(TXD)

CABLE

DB-25 MALE

TOGGLE SWITCHES

CONNECTOR

(SPST)

METHOD TWO

Figure 4-2. Construction Options for Building a Data Terminal Emulator

4-4 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

Switch Functions

Listed below are the functions of the two toggle switches referred to in Figure 4-1. These functions are called for in many of the test procedures which follow.

• Closing SW1 keys the transmitter by setting the RTS line high.

• SW1 must be closed in order for SW2 to emulate transmit data (TXD). Transmit data is emulated as follows:

Closing SW2 emulates a “Space” condition. Opening SW2 emulates a “Mark” condition.

REMOTE MAINTENANCE CONSIDERATIONS General

If your radio is equipped with a Remote Maintenance Module (P/N 05-1958A01 installed in Jacks J5/J7), some of the tests and alignments which follow must be done using software commands from the Hand-Held Terminal (HHT) and not with the on-board adjustments.

The HHT icon shown below indicates that the paragraph to its immediate right describes an action to be taken on transceivers equipped with Remote Maintenance.

The description given below is an example only, and is one of many descriptions of this type in this manual. HHT programming and control commands are shown in uppercase

TYPE.

Table 3-2 contains a complete list of HHT programming and control commands.

BOLD

NOTE

Presettings

The Remote Maintenance Module has three electronic potentiometers (EEPOTs) that are electrically in parallel with the frequency, deviation and RF power potentiometers on the transceiver motherboard. Before any alignment of the transceiver is started, the EEPOTs

Use the SER command to read the serial number assigned to the transceiver.

must be preset to their initial settings (50%) using the

RMIS command from the HHT. The

three potentiometers on the transceiver motherboard must then be preset to the positions listed in Table 4-1.

After the potentiometers on the motherboard are preset, you should adjust the transmitter’s output power (using the HHT) according to the instructions given in Test Procedure ➊. You

should then proceed with the required test procedures listed in Table 4-2.

NOTE

The settings of the EEPOTs can be checked at any time by entering the

RMRD command on the HHT keypad. The HHT

displays the settings of all three EEPOTs on one screen.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-5

Table 4-1. Main Circuit Board Potentiometer Settings for Remote Maintenance

DESIGNATOR FUNCTION POSITION

R69 TX Power Output Maximum CW

R168 TX Deviation Maximum CW

R69 and R168 are multiturn controls that should be advanced at least 10 turns, or until a faintly audible clicking sound is heard from the potentiometer. This sound indicates the end of the control’s range.

After these potentiometers are preset to the positions listed in Table 4-1, the technician should adjust the transmitter’s output power (using the HHT) according to the instructions given in the BASIC TRANSCEIVER TESTS section. (Page 4-7.)

Then, the technician should proceed with the required alignment procedures in the order given below. A separate section is provided for each modem configuration installed in the transceiver—no modem, 1200 bps, 4800 bps, and 9600 bps. These sections cover transceiver adjustments for Transmit Frequency, Squelch, Deviation, and Receive Audio Output.

NOTE

To store Remote Maintenance adjustments, you must

RMST. If the settings are not stored, the radio will

type revert to the previous settings when the power is removed from the transceiver.

INTRODUCTION TO FIELD TESTS & ADJUSTMENTS (See Figure 4-9)

The following test procedures in this chapter are arranged according to the hardware configuration of the MDS 4310 transceiver. The primary difference between units is the presence of a modem—no modem, 1200 bps modem, 4800 bps modem, or 9600 bps modem. There is also a “Basic Tests” section that applies to all radio configurations, and a separate section for adjustment and checkout of the Remote Maintenance Module (if one is installed).

Refer to Table 4-2 to locate the required tests and proceed directly to those sections that apply to your radio. All of these procedures assume the radio is powered up and connected to a dummy load or antenna as required.

Table 4-2. Test Procedure Reference Chart

For alignment instructions relating to... Procedure

Basic Transceiver Checks Radios with no internal modem installed Radios with a 1200 baud modem installed Radios with a 4800 baud modem installed Radios with a 9600 baud modem installed Remote Maintenance Module

—Applies to all radio configurations

(with or without a modem installed)

➊ ➋ ➌ ➍ ➎ ➏

4-6 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

NOTE

The transmitter will be turned off by the time-out timer if the transmit period exceeds the programmed time out value. To continue

testing, simply unkey and key the transmitter to reset

the timer. The factory default value for the time-out timer is 180 seconds.

If desired, the time-out timer may be disabled during these tests, by sending the

DTOT command from the HHT keypad. Be

sure to restore the timer to its original setting when testing is complete.

NOTE

The Diagnostics Channel (the link between the HHT and the radio) “times out” after 15 minutes of no HHT keypad activity. If this happens, you will need to re-open the Diagnostics Channel to resume transceiver testing.

TEST PROCEDURE ➊: BASIC TRANSCEIVER CHECKS—Applicable to all hardware configurations

Introduction

This section describes basic checks that apply to all common configurations of the MDS 4310 transceiver. The checks covered are:

• Power supply

• Transmitter power output

• Antenna VSWR

These checks should be made before starting any detailed troubleshooting or alignment of the transceiver. See Figure 4-9 for the locations of adjustable controls on the transceiver motherboard.

Power Supply Check

1. Connect the power supply to the transceiver.

2. Remove the transceiver’s cover by loosening the four captive screws along the perimeter of the case.

3. Measure the power supply voltage at the transceiver power connector.

With Remote Maintenance installed, the supply voltage can be checked by

entering the SV command on the Hand-Held Terminal.

If necessary, adjust the power supply voltage to 13.8 Vdc. If the voltage is not adjustable, make sure the nominal value is between 12 and 15 volts.

4. Momentarily key the transmitter by the

KEY and DEKEY commands.

5. The voltage should drop no more than 0.4 Vdc while the transceiver is keyed.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-7

Transmitter Power Output Check

1. Connect a directional wattmeter between the transceiver and the antenna feedline.

2. Connect the HHT to the transceiver and open the Diagnostics Channel.

3. Key the transmitter by entering KEY. This command keys the transmitter until the

DKEY command is entered (or until the time-out period has been reached).

4. Check the output power of the transceiver. If necessary, adjust it for the desired level, or a maximum of 5 watts, using R69 on the transceiver motherboard. Do not exceed 5 watts.

IP / DP / INCP / DECP commands to adjust the output power. The IP / DP

commands increment/decrement the power in single steps while the INCP /

If Remote Maintenance is installed, set R69 fully clockwise and use the

DECP

commands make larger jumps by adding a space and a number to the

command. (Example: INCP_20 + out of 100). When finished, type

ENTER

RMST to store the setting.

to increase the power by 20 steps

CAUTION

In systems operating with battery power, make sure that the battery is fully charged before attempting to set the transceiver output power. If the power is set for 5 watts with reduced battery voltage, the transceiver will put out more power when the battery becomes fully charged, which may cause a violation of FCC rules and drain the battery more quickly than expected.

Antenna VSWR Check

1. Connect a directional wattmeter between the transceiver and the antenna feedline.

2. Key the transmitter by entering KEY. This command keys the transmitter until the

DKEY command is entered (or until the time-out period has been reached).

3. With the transmitter keyed, set the directional wattmeter to measure the power in the reverse direction, to measure the reflected power from the antenna. This should read less than 0.5 watt. If the reading is higher, problems with the antenna or feedline are indicated. Check all connections and ensure that the cable connectors are installed properly. Make sure the antenna is not damaged, and is the correct model for this frequency band.

CAUTION

Do not put the radio into service until reflected power problems are corrected, as they can degrade system performance and shorten equipment life.

4-8 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

If an in-line wattmeter is not available, the HHT can be used to obtain a rough indication of the reflected power from the antenna system. Use FPWR to measure forward power, and RPWR to measure the reflected power. The calculated VSWR can be read using the VSWR command.

NOTE

The built-in power output and VSWR metering functions are provided for the convenience of service personnel for making quick checks of the radio’s performance. They are not substitutes for calibrated test equipment.

4. Dekey the transmitter and remove the directional wattmeter from the antenna circuit.

VCO Lock Voltage Adjustment

In order for the radio to switch quickly between transmit and receive, the VCO range capacitor is adjusted so that the lock voltage does not change between transmit and receive modes. This adjustment requires monitoring the lock voltage with a DC voltmeter on the transceiver motherboard or on the HHT using the LV command if the Remote Maintenance Module is installed.

1. Place voltmeter at test point shown in Figure 4-3 or use the HHT to measure the VCO lock voltage. The voltage should be between 2 and 7 Vdc.

2. Key the radio with the KEY command.

3. Monitor the voltage. The nominal voltage is not important, it should not vary more than one tenth of a volt between transmit and receive modes.

4. If the voltage difference is greater than one tenth of a volt, adjust the VCO RANGE capacitor C247, on the transceiver PC board until the lock voltage is the same (± 0.1 Vdc) in the transmit and receive mode. C247 is available through the shield of the VCO sub-assembly.

VCO LOOP VOLTAGE TEST POINT

VCO

ASSEMBLY

SHIELD

C247

VCO RANGE

(THRU SIDE OF

SHIELD)

Figure 4-3. VCO Lock Voltage Test Point

This completes the basic tests of the MDS 4310 Transceiver.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-9

TEST PROCEDURE ➋: TRANSMIT FREQUENCY, SQUELCH, DEVIATION, AND RECEIVE AUDIO OUTPUT—For Radios with No Internal Modem

Remove the cover from the transceiver by loosening the four captive cover screws and lifting it straight up. See Figure 4-9 for the locations of adjustable controls.

Transmit Frequency

1. Connect the transceiver’s ANTENNA connector to the input of the service monitor using a short length of RG-8/U or RG-214 coaxial cable.

2. Key the transmitter by entering KEY on the HHT or use the Transmit Test Switch. The KEY command keys the transmitter until the DKEY command is entered or until the time-out period has passed.

3. Measure the transmitter frequency. It should be within 100 Hz of the assigned frequency. If not, adjust the transmitter frequency on the TCXO.

instead of adjusting the Frequency Adjust on the TCXO. The IF / DF commands increment/decrement the frequency in single steps while the

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commands

INCF / DECF commands make larger jumps by adding a space and a number

to the command. (For example: INCF_8 to increase the frequency by eight steps out of 100.) When finished, type RMST to store the setting.

4. Unkey the transmitter and reconnect the interface cable to the external modem or RTU.

Receive Audio Output Level

The receive audio output level of the transceiver is factory-set for 0.7 Vp-p (–10 dBm) at 600 Ω, at rated system deviation. If a third party modem is used with the MDS 4310, consult its instruction manual to determine what audio input level the modem needs. Should a different level be required, adjust the Receive Audio Output Level, R292, on the transceiver board as follows:

1. Generate an on-channel signal modulated with a 1 kHz tone, at the proper deviation level (commonly 2.5 kHz), to provide an audio signal for adjustment purposes. Monitor the level at the input to the modem (or at Pin 11 of the

INTERFACE

connector) using the oscilloscope in the service monitor. Adjust R25 on the main transceiver board for the desired level.

An alternate method is to adjust R25 when data signals from the master station are present and audio tones can be seen on the scope.

2. Reconnect the feedline directly to the ANTENNA connector of the transceiver. Place the unit in normal operation with the associated master station.

Squelch Adjustment

1. Consult the RTU instruction manual to determine if squelch action in the radio is required for normal operation. If squelch action is not required, set Squelch Threshold, R41, fully counterclockwise (open squelch) and skip the remaining steps of this procedure. If you are unsure on this point, assume that squelch action is

required and perform the following procedures.

2. Remove the feedline from the ANTENNA connector.

4-10 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

3. Using an oscilloscope set for DC coupling at 2 V or 5 V per division, observe the Receiver Unsquelched (RUS) signal at Pin 10 of the INTERFACE connector.

4. Insert an on-channel signal at –120 dBm (.225 µV), with a 1 kHz tone and 2.5 kHz deviation. Adjust R41 fully counterclockwise while observing the oscilloscope display.

5. Set the squelch to be fully closed at this signal level by advancing R41 until the oscilloscope pattern changes from about 8 V to 0 V. Watch for noise on the scope display, and advance R41 slightly farther, if necessary, until the signal level remains at about 0 V.

Transmitter Deviation

1. Inject a test tone equivalent to the RTU audio output level (typically 1200 or 2200 Hz) into the radio at Pin 9 of the INTERFACE connector.

2. Key the transmitter by entering KEY on the HHT, or by grounding the radio’s “not” PTT line (Pin 16).

3. Observe the deviation on the service monitor, and adjust it to 2.5 kHz using R168, TX DEV.

ID / DD / INCD / DECD commands to adjust the deviation. The ID / DD com-

mands increment/decrement the deviation in single steps while the INCD /

If Remote Maintenance is installed, set R168 fully clockwise and use the

DECD

commands make larger jumps by adding a space and a number to the

command. (Example: INCD_4 to increase the deviation by four steps out of

100.) When finished, type RMST to store the setting.

4. Unkey the transmitter using the DKEY command.

5. Close the Diagnostics Channel and disconnect the HHT from the transceiver.

Putting Things Back Together

1. Reconnect feedline and interface cables to transceiver, and reinstall the cover.

2. Confirm that the unit operates properly with the associated RTU. (Typically, the transceiver should be transmitting intermittently in response to polling signals from the master station.

3. Secure all cables, providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the MDS 4310 transceiver without a modem installed.

TEST PROCEDURE ➌: TRANSMIT FREQUENCY, SQUELCH, DEVIATION, AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 1200 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the Data Terminal Emulator (Figures 4-1). See Figure 4-2 for an assembly drawing of the 1200 baud modem. See Figure 4-9 for the locations of adjustable controls on the transceiver mother– board.

Continued on next page.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-11

TEST PROCEDURE ➌: (Continued) TRANSMIT FREQUENCY, SQUELCH, DEVIATION, AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 1200 BPS Modem

Set-up

1. Remove the cover from the transceiver by loosening the four captive cover screws and lifting it straight up.

2. Connect the HHT and open the Diagnostics Channel.

3. Connect the transceiver’s ANTENNA connector to the input of the service monitor using a short length of RG-8/U or RG-214 coaxial cable.

4. Close the Diagnostics Channel and disconnect the HHT.

5. Connect the Data Terminal Emulator to the INTERFACE connector.

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed/SW2 Open). This generates a continuous Mark tone.

2. Measure the transmit carrier frequency; it should be within 100 Hz of the assigned frequency. If not, adjust the transmitter frequency using the Frequency Adjustment on the TCXO.

instead of adjusting the TX Frequency Adjustment control on the TCXO. The IF / DF commands increment/decrement the frequency in single steps while the INCF / DECF commands make larger jumps by adding a space and a number to the command. (For example: INCF_8 to increase the frequency by eight steps out of 100.) When finished, type RMST to store the setting.

Data Deviation

1. Adjust the service monitor to read modulation deviation. With the transmitter still keyed (SW1 Closed), the deviation should be 2.5 kHz ±100 Hz. If not, adjust R168, TX DEV. for the proper deviation.

If Remote Maintenance is installed, set R168 fully clockwise and use the

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commands

ID / DD / INCD / DECD commands to adjust for 2.5 kHz deviation. The ID / DD commands increment/decrement the deviation in single steps while

the INCD / DECD commands make larger jumps by adding a space and a number to the command. (Example: INCD_4 to increase the deviation by four steps out of 100.) When finished, type RMST to store the setting.

2. Measure the Mark tone frequency. It should be 1200 Hz ± 10 Hz. If not, adjust R2 on the modem board.

3. Close SW1 and SW2 to generate a Space tone.

4. Check the transmitter’s deviation. It normally falls within 0.5 kHz of the Mark tone’s deviation.

5. Measure the Space tone’s frequency. It should be 2200 Hz ± 10 Hz. If not, adjust R3, Space, on the modem board.

6. Unkey the transmitter by removing the Data Terminal Emulator.

7. Turn off S1-3 on the modem PC board.

4-12 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

8. Generate an on-channel signal at –60 dBm (225 µV), with 1 kHz modulation at

2.5 kHz deviation.

9. Adjust the transceiver’s R25 for 1.2 Vp-p ± 0.05 V at U3 pin 8 (on the main

transceiver PC board) as read on the oscilloscope.

10. Set the service monitor modulation frequency to 1700 Hz.

11. Touch the oscilloscope probe tip to the top of chip resistor R33 on the modem board.

12. Adjust R25 (on the modem) for a square wave on the scope. Remove the probe.

13. Turn off the service monitor and disconnect the coax from the transceiver’s ANTENNA connector.

14. Adjust the squelch by observing the receiver audio output signal at Pin 11 of the

INTERFACE connector using an oscilloscope.

15. Adjust R41 on the transceiver’s motherboard fully counterclockwise, and observe the noise voltage on the oscilloscope. Now slowly rotate R41 clockwise to a point just beyond that where the noise disappears. Watch the scope for a few seconds and, if necessary, continue to advance R41 until the receiver remains fully squelched (the noise no longer appears intermittently).

SPACE TONE

(2200 HZ)

FREQUENCY

MARK TONE

(1200 HZ)

FREQUENCY

R33

R25

RECEIVE DATA

DETECTOR

THRESHOLD

ADJUST

J6 J8

R33

RX TEST POINT

Figure 4-4. 1200 bps AFSK Modem; MDS P/N 03-1815AXX

See Table A-1 in Appendix A for details on switch settings.

Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe the Receiver Unsquelched (RUS) signal at Pin 10 of the INTERFACE connector.

2. Insert an on-channel signal at –120 dBm, with a 1 kHz tone and 2.5 kHz deviation. Adjust R41, Squelch Threshold, fully counterclockwise while observing the oscilloscope display.

3. Set the squelch to be fully closed at this signal level by advancing R41, Squelch Threshold, until the oscilloscope pattern changes from about 8 V to 0 V. Watch for noise on the scope display, and advance R41 slightly farther, if necessary, until the signal level remains at about 0 V.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-13

Putting Things Back Together

1. Restore the transceiver’s time-out timer to the original value (if changed) using the

PTOT_XXX command on the HHT. The factory default setting is 180 seconds.

2. Reinstall the cover. Reconnect the antenna feedline and reconnect the RTU’s interface cables to the transceiver.

3. Confirm that the unit operates normally with the associated RTU.

4. Secure all cables, providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the transceiver with a 1200 baud modem installed. For additional information on the 1200 baud modem refer to Appendix A.

TEST PROCEDURE ➍: TRANSMIT FREQUENCY, SQUELCH, DEVIATION, AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 4800 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the Data Terminal Emulator (Figure 4-2). See Figure 4-5 for an assembly drawing of the 4800 baud Modem. See Figure 4-9 for the locations of adjustable controls on the transceiver motherboard.

Set-up

1. Remove the cover from the transceiver by loosening the four captive cover screws and lifting it straight up. Make a list of the settings of configuration switch S1 on the modem—they will be changed temporarily during the alignment procedure.

2. Close the Diagnostics Channel and disconnect the HHT.

3. Connect the Data Terminal Emulator to the INTERFACE connector.

4. Connect the transceiver’s ANTENNA connector to the input of the service monitor using a short length of RG-8/U or RG-214 coaxial cable. Set up the service monitor to monitor the transmitter’s center (channel) frequency.

5. Set the transmitter deviation to minimum by rotating R168, Deviation, fully counter clockwise.

6. On the modem, set S1 to positions 2 and 4 ON (Closed), all others OFF (Open).

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed). The TXD line should be at logic low (LED annunciator TD [TXD] off).

2. Check for correct transmit center frequency. With TXD low (SW2 Open) the transmitted frequency should be within 100 Hz of the assigned center frequency. If necessary, adjust the TX Frequency Adjustment control on the TCXO.

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commands

instead of the adjustment on the TCXO. The IF / DF commands increment/decrement the frequency in single steps while the INCF / DECF commands make larger jumps by adding a space and a number to the command. (For example: INCF_8 to increase the frequency by eight steps out of 100.) When finished, type RMST to store the setting.

4-14 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

Data Deviation

(

)

1. With the transmitter still keyed (SW1 Closed), increase the deviation by rotating R168 clockwise to cause the frequency to shift down from the assigned center frequency by 1.6 kHz ± 75 Hz.

and use the ID / DD / INCD / DECD commands to set the downward frequency shift to 1.6 kHz. The ID / DD commands increment/decrement the deviation in single steps while the INCD / DECD commands make larger jumps by adding a space and a number to the command. (Example: INCD_4 to increase the deviation by four steps out of 100.) When finished, type RMST to store the setting.

2. Set the TXD line high (SW2 Closed). Observe the carrier frequency shifting up 1.6 kHz ± 75 Hz from the assigned center frequency. If it does not, alternately adjust the TX Frequency adjustment on the TCXO and R168, checking both high and low frequencies for equal 1.6 kHz shifts.

Note—There is some interaction between R168 and the TX Frequency adjustment on the TCXO. If the shift is equal in both directions, but exceeds 1.6 kHz, it may be necessary to turn the deviation down slightly and repeat this step. Continue to alternately adjust R168 and the TX Frequency adjustment on the TCXO until equal

1.6 kHz shifts are obtained.

3. Set RTS and TXD low (SW1 and SW2 Open).

4. Set S1-3 on the modem to ON. This generates a data test pattern of 101010.

5. Set RTS high (SW1 Closed).

CONFIGURATION

If Remote Maintenance is installed, set R168 to its full-clockwise position

8 1

Pin 3

P8 P6

CLOSED

OFF (OPEN)

Figure 4-5. 4800 BPS FSK Modem; MDS P/N 03-1831A01

See Table B-1 in Appendix B for details on switch settings.

6. Adjust the HF Audio Compensation control, R179, if necessary, to produce 2.7 kHz ±75 Hz deviation as measured on the service monitor.

7. Set RTS low (SW1 Open) and turn OFF S1-3 on the modem.

8. Set the service monitor to generate a –60 dBm (225 µV) on-channel signal with a 1 kHz tone at 2.5 kHz deviation.

9. Connect an oscilloscope set to a 5 ms timebase to U3 Pin 3 on the modem. Adjust R25 (Receive Audio Level) on the transceiver’s motherboard for a waveform showing a 0.7 to 0.75 Vp-p sinewave riding on 2.5 Vdc.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-15

Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe the Receiver Unsquelched (RUS) signal at Pin 10 of the radio’s INTERFACE connector.

2. Insert an on-channel signal at –120 dBm (.225µV), with a 1 kHz tone and 2.5 kHz deviation. Adjust R41, Squelch Threshold, fully counterclockwise while observing the oscilloscope display.

3. Set the squelch to be fully closed at this signal level by advancing R41 until the oscilloscope pattern changes from about 8 V to 0 V. Watch for noise on the scope display, and advance R41 slightly farther, if necessary, until the signal level remains at about 0 V.

Putting Things Back Together

1. Restore the transceiver’s time-out timer duration to the original value (if changed) using the PTOT_XXX command on the HHT.

2. Restore the modem’s Configuration Switch, S1, to its original settings or as recommended in Table B-1 of Appendix B of this manual.

3. Reconnect the RTU’s interface cables to the transceiver and reinstall the cover. Reconnect the antenna feedline.

4. Confirm that the unit operates normally with the associated RTU. Secure all cables, providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the transceiver with a 4800 baud modem installed. For additional information on the 4800 baud modem refer to Appendix B.

TEST PROCEDURE ➎: TRANSMIT FREQUENCY, SQUELCH, DEVIATION, AND RECEIVE AUDIO OUTPUT—For Units with MDS’s Internal 9600 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the Data Terminal Emulator (Figure 4-2). See Figure 4-6 for an assembly drawing of the 9600 baud Modem. See Figure 4-9 for the locations of adjustable controls on the transceiver motherboard.

Set-up

2. Close the Diagnostics Channel and disconnect the HHT.

3. Connect the Data Terminal Emulator to the INTERFACE connector.

5. Set the transmitter deviation to minimum by rotating R168, Deviation, fully counter clockwise.

6. On the modem, set S1 to 6 & 7 ON (Closed), all others OFF (Open).

4-16 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

(

)

CONFIGURATION

8 1 OFF (OPEN)

Pin 7

P8 P6

CLOSED

Figure 4-6. 9600 BPS FSK Modem; MDS P/N 03-1833A01

See Table C-1 in Appendix C for details on switch settings.

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed). The TXD line should be at logic low (LED annunciator TD [TXD] off).

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commands

instead of adjusting the TX Frequency adjustment on the TCXO. The IF / DF commands increment/decrement the frequency in single steps while the

INCF / DECF commands make larger jumps by adding a space and a number

to the command. (For example: INCF_8 to increase the frequency by eight steps out of 100.) When finished, type RMST to store the setting.

Data Deviation

1. With the radio still keyed (SW1 Closed), raise TXD (SW2 Closed). This should cause the transmitted frequency to shift by 1.6 kHz ±75 Hz either up or down.

It does not matter if the frequency shifts up or down; the way it shifts depends only upon the phase of the modem’s internal 9600 Hz clock at the instant the TXD line changed. If the TXD line is toggled, the transmit frequency should change between

the assigned center frequency when TXD is low and 1.6 kHz on either side of center when TXD is high. If necessary, adjust R168 on the transceiver motherboard to obtain a 1.6 kHz ±75 Hz shift.

If Remote Maintenance is installed, set R168 to its full-clockwise position

and use the ID / DD / INCD / DECD commands to set the frequency shift to

1.6 kHz. The ID / DD commands increment/decrement the deviation in single steps while the INCD / DECD commands make larger jumps by adding a space and a number to the command. (Example: INCD_4 to increase the deviation by four steps out of 100.) When finished, type RMST to store the setting.

2. Toggle TXD high (SW2 Closed) until the frequency shifts opposite from above. The frequency should shift 1.6 kHz ±75 Hz. If not, alternately adjust the TX Frequency adjustment on the TCXO and R168 on the transceiver’s motherboard, toggling TXD, checking both the high and low frequencies for equal 1.6 kHz shifts.

Continued on next page.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-17

Data Deviation (Continued)

1.6 kHz shifts are obtained.

3. With the high and low shifts equal, set TXD low (SW2 Open). The transmit

frequency should be within ± 200 Hz of the assigned (channel) frequency. If not, adjust the TX Frequency adjustment on the TCXO as described in the Transmit Frequency procedure above.

4. Set RTS high (SW1 Closed) and turn ON S1-3 on the modem.

5. Adjust the Transmitter HF Audio Compensation control, R179, if necessary, to

produce 2.7 kHz ± 75 Hz deviation as measured on the service monitor.

6. Unkey the radio by setting RTS low (SW1 OPEN).

7. Turn OFF S1-3 on the modem.

Receive Audio Output Adjustment

1. Generate a –60 dBm (225 µV) signal on the receive frequency with 1 kHz

modulation at 2.5 kHz deviation.

2. Using an oscilloscope set to a 5 ms timebase, observe the waveform at U3 Pin 7 on the modem board; it should be a 0.7 to 0.75 Vp-p sinewave riding on 2.5 Vdc. If not, adjust the Receive Audio Level control, R25 (on the transceiver’s motherboard), to produce 0.7 to 0.75 Vp-p at TP1.

Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe the Receiver Unsquelched (RUS) signal at Pin 10 of the

INTERFACE connector.

2. Insert an on-channel signal at –120 dBm (.225 µV), with a 1 kHz tone and 2.5 kHz deviation. Adjust R41, Squelch Threshold, fully counterclockwise while observing the oscilloscope display.

Putting Things Back Together

1. Restore the transceiver’s time-out timer duration to the original value (if changed) using the PTOT_XXX command on the HHT.

2. Restore the modem’s Configuration Switch, S1, to its original settings or as recommended in Table C-1 of Appendix C.

3. Reconnect the RTU’s interface cables to the transceiver and reinstall the cover. Reconnect the antenna feedline.

4. Confirm that the unit operates normally with the associated RTU. Secure all cables, providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the transceiver with a 9600 baud modem installed. For additional information on the 9600 baud modem refer to Appendix C in this manual.

4-18 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

TEST PROCEDURE ➏: REMOTE MAINTENANCE MODULE— Loopback Code Programming, Mode Selection, Calibration & Testing

Introduction

The Remote Maintenance Module (Figure 4-7) is a small PC board assembly that mounts vertically into Jacks J5 and J7 of the transceiver PC board. The module contains two adjustable controls—Loopback TX Audio Level (R6), and Temperature Setting (R33).

Normally, R6 needs adjustment only when the module is first installed in the radio. R33 is adjusted at the factory.

The following procedures are not required for units shipped from the factory with Remote Maintenance installed. Perform these procedures only if the Remote Maintenance Module is being newly installed, is known to be out of adjustment, or if the Remote Maintenance Module is being replaced.

NOTE

If you are unsure whether a Remote Maintenance Module is installed in the transceiver, open the Diagnostics Channel with the Hand-Held Terminal and enter the

STAT command. The

display responds with the type of diagnostics that are installed in the transceiver. The forth character will show an I if the module is installed, or a U if it is not installed. (See Table 3-2 to interpret the full response.)

LOOPBACK TX

AUDIO LEVEL

R33

TEMP. SET

J7 J5

Figure 4-7. Remote Maintenance Module (P/N 03-1958A01)

NOTE

In a properly aligned system, Remote Maintenance provides valuable information to service personnel, however, it is not a substitute for calibrated test equipment.

Loopback Code Identification

A loopback code is used to identify the radio during diagnostics operations. Each radio in the system must have a unique four digit numerical loopback code for Remote Maintenance diagnostics to work properly. The code should be one that is not being used elsewhere in the system in which the radio will be installed; duplicate codes can cause failure in or incorrect data from radios having the same loopback codes.

To determine the current loopback code, connect the HHT to the radio and open the Diagnostics Channel. Next, type

LBC. The radio responds by displaying the code on the HHT

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-19

display. (Units shipped from the factory are pre-programmed with a default loopback code consisting of the last four digits of the radio’s serial number.)

The displayed loopback code is followed by the characters

UI (uninstalled) or I (installed) at

the end of the second line in the display to indicate the presence of a Remote Maintenance Module. If no loopback code has been entered, the indication will be UI for uninstalled, even if the module is present, since a valid loopback code has not been entered. When the loopback code is entered, and the radio is shut down and re-powered up, the indicator will be

I for installed.

Programming a New Loopback Code

If you wish to program a new loopback code, type “_”, is a space and “

XXXX” is a four digit address code. This code identifies the unit during

PLBC_XXXX, where the underline character,

diagnostic polling by the master station. Note—the code must contain four digits and no letters. After the new loopback code has been entered, the radio responds by displaying the

code on the HHT display.

Diagnostics Mode Selection

The Remote Maintenance Module can be set for one of three levels (modes) of diagnostics and control. The

MODE command is used to set the diagnostics and control mode. Review

Table 3-1—Diagnostics and Control Capabilities for detailed descriptions of the three operating modes. MODE_3xxxx is used to invoke Remote Maintenance, the highest level of diagnostics. Since it provides the highest level of diagnostics and control, many users prefer to keep the radio set up for Remote Maintenance.

Diagnostics Deviation Adjustment

1. Loosen the four cover screws and remove the top cover from the transceiver by lifting straight up.

2. Connect the transceiver’s ANTENNA connector to the input of the service monitor using a short length of RG-8/U or RG-214 coaxial cable.

3. Set the service monitor to receive at the transceiver’s transmit frequency.

4. Connect the transceiver’s power cord and apply power.

5. With the Hand-Held Terminal (HHT) connected to the INTERFACE connector, open the Diagnostics Channel using the OPEN command.

6. If Remote Maintenance is not already enabled, type MODE 3 xxxx, where xxxx is the speed in bits per second (i.e., 1200, 4800 or 9600 bps) of the internal data modem plugged into Jacks J6 and J8. If the radio is not equipped with an internal MDS modem, use MODE 3 1200.

7. Type TEST_1 to activate a DTMF test tone and key the transmitter.

8. Measure the transmitter deviation on the service monitor. If the deviation is not

2.5 kHz, adjust it to 2.5 kHz using R6, TX Audio, on the Remote Maintenance Module. (See Figure 4-6.)

9. Type

TEST_2 to disable the test tone and unkey the transmitter.

Temperature Calibration

The Remote Maintenance Module has a built-in temperature sensor used to measure the radio’s internal temperature during operation. The temperature sensor has been calibrated at the

4-20 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

factory and the need for field adjustment of this parameter is rare. Nevertheless, instructions are given below. If the temperature calibration is misadjusted, its value in remote (over-theair) and local diagnostics will be compromised.

1. Measure the temperature at or near the transceiver chassis using a thermometer that

is accurate to 1°C. The transceiver must be at room temperature.

2. Use the TEMP command to obtain the temperature reading for the radio. The reading is in degrees Celsius.

3. If there is a difference between the thermometer reading and the TEMP indication, adjust potentiometer R33, TEMP SET, on the Remote Maintenance Board to obtain a match between the measurements taken on the HHT and those taken with the thermometer. (See Figure 4-7.) The measurement given by the HHT is updated once per second. That is, the TEMP command does not have to be invoked after each adjustment of R33.

4. Close the Diagnostics Channel to the transceiver. and disconnect the HHT.

5. Reinstall the cover on the transceiver.

Forward Power & RSSI Calibration

If a Remote Maintenance Module is added to a transceiver as a field upgrade, or a module is transferred from one radio to another, two diagnostic measurements need calibration for maximum accuracy. These are the forward power (

FPWR) and received signal strength (RSSI)

functions.

Procedure

1. Connect a 50 Ω dummy load through a directional wattmeter to the ANTENNA connector of the transceiver.

2. Connect the HHT to the INTERFACE connector of the transceiver.

3. Key the transmitter with the

KEY command from the HHT. Type KEY + ENTER .

4. Set the transmit power output to 5 watts using the TX Power Output level control, R69, on the transceiver motherboard as indicated on the in-line directional wattmeter.

5. Enter the calibrate power command, CPWR, from the HHT. Type CPWR + ENTER . The forward and reflected power detectors will be automatically calibrated.

6. Dekey the transmitter with the DKEY command from the HHT. Type DKEY + ENTER .

7. Disconnect the directional wattmeter and dummy load from the

ANTENNA connector.

8. Connect a communications service monitor to the ANTENNA connector.

9. Inject an on-channel unmodulated –110 dBm (.710 µV) signal.

10. Enter the calibrate received signal strength low level command, RSSL, from the HHT. Type

RSSL + ENTER . The low level RSSI calibration point is automatically

calibrated.

11. Increase the signal level to –60 dBm (225 µV) signal.

12. Enter the calibrate received signal strength high level command, RSSH, from the HHT. Type RSSH + ENTER . The high level RSSI calibration point will be automatically calibrated.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-21

13. Enter the received signal strength command, RSSI, from the HHT. Type RSSI +

ENTER . The display shows the current received signal level in dBm. Check the

calibration with the communications service monitor set between –60 dBm (225 µV) and –120 dBm (.225 µV).

14. This completes the calibration procedure. Disconnect the HHT and communications service monitor.

Testing The Remote Transceiver With The Master Station—Optional Checkout

This section provides abbreviated instructions for testing Remote Maintenance with a properly equipped Master station on a service bench. This test simulates over-the-air Remote Maintenance using a PC and MDS 2000 Diagnostics and Control System software. Complete instructions for using the software are contained in the MDS 2000 Diagnostics and Control System software User’s Guide (P/N 05-1919A01).

1. Connect the transceiver to the Master Station using coaxial cable through at least 100 dB of attenuation. The attenuators at each end of the connection should be rated to continuously withstand at least 5 watts of RF power.

2. Attach the PC through one of its serial ports to the

DIAGNOSTIC connector on the rear

of the MDS 2100 Master Station.

3. Set the Master Station’s rear-panel DTE/DCE switch to DCE if you’re using a straight-through serial cable, or DTE if you’re using a null-modem cable.

4. Load the MDS 2000 Diagnostics and Control System software on the PC and open the Diagnostics Channel to the Master Station.

5. Using the software’s Equipment List Editor, select the Remote transceiver to be tested and set the radio’s diagnostic level to Remote Maintenance.

6. Return to the polling screen and verify that you can perform a diagnostic poll on the remote radio.

7. Press

F4 to invoke Remote Maintenance. The Remote Maintenance screen for that

transceiver appears. (See Figure 4-8.)

8. The software displays the Remote radio’s transmit frequency error compared to the master station’s receive frequency. The offset (or difference) should be within 0.3 kHz; If not, adjust the MDS 4310 transmit frequency as described in the Field Alignment instructions in this chapter.

9. Verify that the DTMF deviation display indicates approximately 2.5 kHz. If no modem is installed in the transceiver, skip ahead to Step 11. Otherwise, proceed with Step 10.

10. Press F3 to toggle the deviation display from DTMF to DATA. If the data deviation is 2.7 kHz ±0.2 kHz, proceed to the next step. If not, adjust the MDS 4310 deviation as described in the Field Alignment instructions in this chapter.

11. If the power output is not set to the desired output level (usually 5 watts), use the

← → arrow keys to select the POWER bar and the ↑ ↓ arrow keys to increase or

decrease the output level as desired. The POWER bar also shows the reflected power level and includes a VSWR summary—OK, CHECK SYS, or BAD.

12. Press F4 to store the changes within the Remote Maintenance Module.

13. Press

Esc to close Remote Maintenance of that Remote unit and return to the

previous screen.

4-22 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

14. This completes the Remote Maintenance checkout procedure. For additional information on the Remote Maintenance Module refer to Appendix D.

MICROWAVE DATA SYSTEMS -- REMOTE MAINTENANCE

Press (Esc) to Exit or Use (Arrow) keys to select and change a Control Setting [F2] Update Screen [F4] Store Changes [F3] Toggle DTMF/DATA Deviation Display [F6] AFC Off [F7] Rx AFC [F8] Tx/Rx AFC AFC is currently set to (OFF)

--- REMOTE UNIT (8802) --SUPPLY

VOLTAGE

13.9V

15 14 13

12 11

POWER (W) REF / FWD / VSWR

0.3 / 4.8 / OK

9.0

7.5

6.0

4.5

3.0

1.5 0

TEMPERATURE

ADJUSTMENT

STATUS

REMOTE UNIT

+25.0°C

--- REMOTE CONTROL SETTINGS -POWER

[ 56 ]

--- MASTER MONITORING OF --

SIGNAL

STRENGTH

–59dBm

–50

–60 –70 –80

–90

–100

–110

+6.0

+4.0 +2.0

–2.0 –4.0

–6.0

FREQ

OFFSET

0.3KHz

DATA DEV.

DEVIATION

6.0

5.0

4.0

3.0

2.0

1.0 0

DATA

2.6KHz

Figure 4-8. Remote Maintenance Screen

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-23

This page intentionally blank

4-24 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

OPTION BOARD 1

J6 & J8

R25

RECEIVE

AUDIO LEVEL

J16

FULL DUPLEX

INTERFACE

J14

RX AUDIO

NORMAL/INVERT

OPTION BOARD 2

J5 & J7

EXTERNAL

INTERFACE

J11

SHUNT AS

REQUIRED

LED

INDICATORS

DC POWER

INPUT

4A FUSE

R41

SQUELCH

THRESHOLD

DISABLE RS-232

ENABLE

LED

ANTENNA

J7 J5

INV.

L25

R69

TX POWER

OUTPUT

NORM

TX FREQ.

R168

TX DEV.

R179

HF AUDIO

COMP.

C247

VCO RANGE

(THRU SIDE OF SHIELD)

Figure 4-9

MDS 4310 Transceiver 2314Axx PC Board

Test Points and Adjustments

Potentiometer types may differ from those shown.

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-25/26

CHAPTER 5—THEORY OF

OPERATION

For the following discussion, see Figure 5-1, the radio’s block diagram at the end of this chapter.

RECEIVE FRONT END

Connector J4 on the main PC board conducts the RF signal from the front panel ANTENNA connector to the antenna switch network. In the receive mode, one port of the antenna switch conducts the receive signal to the input of helical filter Z1.

The output of Z1 is fed to RF amplifier Q1. The output of Q1 goes to helical filter Z2. The output of Z2 goes to M1, a double-balanced mixer whose local oscillator injection signal is derived from the VCO output.

HIGH IF

The 45 MHz High IF signal from M1 enters the IF amplifier. The output of IF amplifier connects to L25 as an input matching transformer. The receive signal is then passed to FL1A and FL1B. FL1A and FL1B are components of a 4-pole crystal filter that provides some of the IF selectivity of the receiver. The output of FL1B is conducted to U32, which contains the low IF amplifier and other functions.

LOW IF

U32 contains several circuit sections: mixer, oscillator, IF amplifier/limiter, quadrature detector and received signal strength indication driver. The second 44.55 MHz LO for U32 is derived from the TCXO. A frequency tripling circuit multiplies the 14.85 MHz TCXO signal and triples it up to 44.55 MHz. This is consequently mixed with the 45 MHz IF to form the 450 kHz IF.

The 450 kHz output of the second mixer is fed to a ceramic filter set consisting of FL2 and FL3. This filter set provides the main adjacent channel selectivity of the receiver.

The output of FL3 is fed to the limiter amplifier input pin of U32. The limiter output is fed to a quadrature detector circuit tuned by discriminator coil T1; recovered audio is passed to U3A audio buffer.

A secondary output of the IF subsystem of U32 gives a received signal strength indication (RSSI) voltage. The RSSI signal is used by the remote maintenance module and is available

INTERFACE connector J1-21 through a buffer and scaler, U3C.

at the

RECEIVE AUDIO

The unfiltered recovered audio from the IF discriminator passes through amplifiers U3A, U3B and configuration jumper J14.

MDS 05-2415A01, Rev. A 5-1

The output of the squelch gate goes to the modem receive audio amplifier, U5A. U5A is an amplifier with the gain set by potentiometer R25. R25 is used to adjust the receive audio level supplied to the modem and remote maintenance boards.

U5D and U5C are an audio lowpass filter that removes noise from the receive audio. The output of this filter goes to external modems through J1.

SQUELCH

The squelch circuit consists of a high-pass filter, noise amplifier, noise rectifier and a comparator.

The high pass filter U6A removes low frequencies of the detected IF output. The output of U6A goes to a gain stage, U6B, which amplifies the high frequency noise. The gain of U6B is set by R41, which is the squelch threshold adjustment.

The amplified high frequency noise output from U6B goes to a full-wave rectifier, which compares this DC voltage with a fixed reference voltage. U6C, which rectifies the noise signal. The output of this stage goes to a squelch comparator, U6D whose output is the receiver unsquelch sensor (RUS) line, and is used to control squelch gate U26A in the receive audio path. This gate is also controlled by the RX MUTE signal from U19D.

The RUS logic signal is also fed to the modem and is used to gate the DCD output from the modem. In addition, this signal appears at J1 pin 10 through a 1 kΩ resistor.

POWER SUPPLY

The + 13 volt DC input appears when an external power source is connected to J2. From J2, the + 13V is conducted to the internal transceiver circuits through F1, a 4 ampere fuse. The fuse protects the transceiver in the event the external, in-line fuse is either defeated or replaced with one of a higher rating.

Z4 is a EMI power line filter. C77 is a electrolytic capacitor. These two devices help provide a noise free power source for the transceiver circuits. A 17 volt zener diode across C77 provides over-voltage and reverse polarity protection.

U38 provides a regulated + 8 volts for most transceiver circuits. U13 provides a regulated + 5 volts, which supplies power to the microcontroller and the logic circuitry.

U45 is a low voltage protection device. It will disable the radio when the input voltage becomes less than 10 volts. The output from U45 drives the radio disable circuit Q15 which disables the 8 volt and 5 volt regulators, U38 and U13.

A precision reference DC voltage of + 2.5V is supplied by U4; this is used by the FSK modem circuitry.

The RX/TX signal from the microcontroller applies + 8 volts to the RF amplifier, high IF amplifier and tripler circuit in the receive mode, and is shut off in the transmit mode.

Q19 supplies a biasing signal to the transmitter amplifiers and antenna switch. Q19 is turned on during transmit by the microcontroller.

The main transmit power control signal from the microcontroller, TXE2, is first conditioned by U46 whose output is sent to the power control potentiometer R69. The wiper of R69 is connected to U44B which is a power-leveling circuit. U44B drives U44A, Q41 and Q43 which form an adjustable voltage regulator. The output of this regulator feeds the power control pin on U33

5-2 THEORY OF OPERATION MDS 05-2415A01, Rev. A

The transmitter can be turned off, independent of microcontroller control, by the synthesizer out-of-lock signal. An out-of-lock condition at the synthesizer will bring the O/L line high, overriding the power control signal TXE2.

TRANSMIT POWER AMPLIFIER

The power amplifier chain of the transmitter section consists of U40 and U33. U40 is a driving amplifier for U33. The output of U40 is fed to hybrid power module U33. The power control of U33 is controlled by the power control regulator Q3 and U44A.

The RF output of U33 is fed through a directional coupler to the antenna switching network.

ANTENNA SWITCH

The antenna switch consists of PIN diodes and a filter network. In the receive mode, PIN diodes are unbiased and effectively disconnected from the circuit. Under this circumstance, the received signal is free to pass to the input of helical resonator Z1 through a low pass filter.

During the transmit mode, the PIN diodes are biased ON by the Q19. When the diodes are conducting, one diode provides a low impedance path for the transmit signal to the

ANTENNA

connector and the other diode shorts out the capacitor in the switching circuit. With the capacitor shorted, the filter network is equivalent to a quarter wave transmission line with no RF current flowing through the inductor.

DIRECTIONAL COUPLER

The directional coupler is used during diagnostic measurements of forward and reflected power at the ANTENNA connector. The directional coupler consists of an in-line transmission line section that conducts RF energy from power amplifier U33 to the antenna switch. Coupled line sections located immediately adjacent to, and either side of the transmission line, receive a sample of the RF energy passing through the coupler. Rectifiers mounted on each end of coupled line sections produce DC voltages. These DC voltages are proportional to the power levels appearing on the coupled lines.

The directional coupler provides a forward power measurement that can be displayed through local diagnostics when the radio has the Remote Maintenance Module installed.

KEYLINE AND CONTROL CIRCUITS

There are three push-to-talk (PTT) inputs to the keyline control circuit. Three negative inputs and one positive going input. The negative going inputs come from J1-16, the modem, and the audio processing board. These are inverted and added to the positive going input coming from J1 pin 14. This signal drives the keyline inverter U19A.

RADIO DISABLE

J1-Pin 12, is the input to the radio disable circuit. The radio disable circuit minimizes power consumption by shutting off all of the transceiver circuits except for Q15 and CR32B. This allows the user to inhibit transceiver functions with an open-collector interface circuit.

J1-Pin 12 should be left open to permit the transceiver to function normally.

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-3

If J1-Pin 12 is grounded U13 and U38 are disabled. Since U38 supplies current to nearly all of the transceiver circuits, current consumption in the transceiver is reduced essentially to zero. This eliminates the need to externally switch the +13 volts applied to the transceiver.

AUDIO/DATA MODULATION INPUT SWITCHING

One section of U15, switch U15X, controls data appearing at the RXD terminal, Pin 3 of J1, switching between modem data and microcontroller data from U16. Another section, U15Z, switches the transmit audio path between the modem transmit audio output and the external transmit audio input to the transceiver from J1.

U15Z is controlled by means of a modem enable line which is tied to +10 volts when the modem option is installed.

Without the modem installed, the normal state of U15Z is such that transmit audio from J1 Pin 9 modulates the transmitter. With the modem installed, the external transmit audio from J1 is cut off, and modem transmit audio is selected.

Should the positive-going push-to-talk (PTT) input on J1-14 be driven high (to key the transmitter—such as when the external order wire option is used), U19B pulls the control line for U15Z low. This allows external transmit audio in from J1 to modulate the transmitter, and cuts off any audio coming from the modem.

MICROCONTROLLER/EEPROM

The microcontroller, U16, controls many of the on-board functions of the transceiver. Some of the control functions are:

• Frequency Programming and Control of the Synthesizer

• Modem RTS/CTS Delay

• Transmitter Time-out Timer

• Transmit Soft Carrier Dekey Delay

• Transmit Squelch Tail Eliminator Delay

• Loopback/Diagnostic Functions

U16 runs a predetermined routine that controls its functions; this routine is permanently programmed within the IC and cannot be altered. All programmable functions and values are stored by the microcontroller in an electrically erasable, programmable, read-only memory (EEPROM) IC, U18. These include operating parameters such as frequency, time-out timer limits, soft carrier dekey times, and CTS delay time, as well as model and factory serial numbers. U16 and U18 share a common clock and exchange data through data lines.

The microcontroller can be reset by several different means. An error output from U13 drives the reset line low causing the microcontroller to reset or the internal modem can drive the reset line from J8. The error signal from U13 resets U16 allowing a stable initialization when 13 Vdc is first applied to the transceiver.

The inhibit line on U13 is controlled indirectly by the radio enable line available at J1-12. The inhibit line on U13 will force a microcontroller reset through the error output line.

5-4 THEORY OF OPERATION MDS 05-2415A01, Rev. A

DIAGNOSTICS DATA CONTROL

Communications between the microcontroller U16 and an external terminal, PC or the HHT is accomplished by means of the TXD (J1–Pin 2) and RXD (J1–Pin 3).

U16 constantly monitors transmit data input on J1–Pin 2, and ignores all data unless the OPEN command from the external programmer is detected or a ground is detected on J1–Pin

23. The receive data output on J1–Pin 3 is normally connected to the output of the modem demodulator when a modem is used. When the OPEN command is detected, U16 switches the receive data path from the modem to its own data output port in order to allow it to communicate directly with the terminal.

The receive data control pin of U16 controls the normally high base of Q8. When the diagnostic channel is opened, Q8 is turned off, thus switching the state of gate U15X. This allows data from the microcontroller to appear at the RXD output (J1-Pin 3).

TRANSMIT AUDIO

The transmit audio circuit consists of a variable gain amplifier, active low-pass filter, and a summing amplifier. The variable gain amplifier U28C gain is set by R168. The transmit audio then passes through a low pass filter consisting of U28B and associated components. The output of U28B, and transmit audio from the remote maintenance board, are summed together in amplifier U28D.

Transmit audio is also fed to the VCO input by means of a R179, which is the high frequency (HF) compensation control. This control provides a balanced transmit audio frequency response.

PLL/SYNTHESIZER

The temperature compensated 14.85 MHz crystal oscillator (TCXO) generates the reference frequency for the phase-lock loop (PLL) circuit.

U36 is a CMOS PLL synthesizer consisting of a phase detector, a programmable reference divider, a programmable feedback divider, and prescaler. Data input is serially loaded from U16; this data consists of binary coded numbers representing the reference and feedback (VCO RF sample) divider ratios required to produce the final transmit frequency. The reference divider is programmed only on power-up, with a power reset or with a PLL out-of-lock condition. The feedback divider value changes according to the transmit/receive frequencies entered by the

PTX and PRX commands, and is reloaded from the EEPROM every

time a transmit-to-receive or receive-to-transmit transition occurs. The phase detector output of U36 is fed to the VCO tuning input through an R-C loop filter.

A sample of transmit audio modulation of the VCO is fed to the loop filter from the wiper of R179.

The lock detector output of U36 is applied to U28A. When the PLL is in lock, U36 shuts off U28A and keeps the O/L line low. An out-of-lock condition causes U28 to drive the O/L line high. The O/L line inhibits the transmit regulator, as previously described in the POWER SUPPLY section; also, it is conducted to J1-Pin 25, through a 1 kΩ resistor.

RS-232 DATA INTERFACE

U31 is an RS-232 line driver/receiver integrated circuit with an input/output disable function. It has an internal +5 volts to ±10 volt converter that allows it to provide an RS-232

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-5

compatible output. Transient protection for the five RS-232 I/O lines from J1 is accomplished by means of zener protection diodes. Static discharge or over-voltage condition appearing on J1 will be shunted to ground with these devices before reaching U31.

In the data signal interface between the plug-in modem assembly and the main transceiver board (i.e., the plug in modem option), the signals are inverted from standard RS-232 signal polarity. The inverted signals, namely RXD(L), TXD(L), DCD(L), RTS(L), and CTS(L), are fed directly to U31.

Header J11 allows the TTL option to be selected. When the pins 1 and 2 of J11 are connected together, U31 is disabled. This effectively removes U31 from the circuit.

LED INDICATORS

U29 and U5 drive the LEDs. U29 is a non-inverting buffer. A jumper across J11, pins 3 and 4 is required to enable the LEDs.

PWR

This LED, CR31B, is illuminated if more than 10 volts is applied to the radio. It flashes if the VCO is Out-of-Lock. U5B is a flasher circuit.

RTS

This LED, CR31A, is illuminated if any of the Push-To-Talk lines is active.

This LED, CR32B, is illuminated if the transmitter power control is active.

TXD

This LED, CR32A, is illuminated if the RS-232 transmit data line is low.

This LED, CR33B, is illuminated if the receiver detects a carrier strong enough to break squelch.

RXD

This LED, CR33A, is illuminated if the RS-232 receive data line is low.

5-6 THEORY OF OPERATION MDS 05-2415A01, Rev. A

RSSI AMP

DISCRIMINATOR

FL2 FL3

CRYSTAL FILTER

RSSI

(J1-21)

AUDIO BUFFER

U32

FL1AFL1

45 MHZ

HIGH IF AMP

MODEM AF

R25

MODEM RX LEVEL ADJUST

U26A

SQUELCH GATE

AUDIO

INVERT

U3A

44.55 MHZ

IF SUBSYSTEM

FREQ.

TRIPLER

(J6-1)

RTS(J6-

(J6-17)

RX AUDIO

RUS

(J1-11)

R41

SQUELCH

U5C

U6D

COMPARATOR

U6C

U6B

NOISE FILTER

(J1-10)

NOISE RECT

NOISE AMP

U6A

VOX AF

RX MUTE

INVERTER

12)

S(J6-

J5, J7

TO OPTION 2

(DIAGNOSTICS BD.)

EEPROM

TX /

U18

REGULATO

X(J1-

L17

RXD(J1-

3.6864 MHZ

LINE

DRIVER

RECEIVER

S(J1-

U31

U16

MICROPROCESSOR

U36

SYNTHESIZER

S(J1-

DCD(J1-

J11

& PRESCALER

LOOP FILTER

VCO

U41

BUFFER

(OUT)

RS-232

C24

(J6-

ENABLE

CLK(J1-

CLK

(J1-

15)

(J6-

21)

23)

(IN) TLL

ENABLE

OUT-OF-LOCK

DET. DRIVER

U28

VCO SAMPLE

17)

EXT.

CLK(J1-

(J6-

14.85 MHZ REF.

24)

20)

+ 5V

R179COMP

HF AUDIO

LOW VOLTAGE

2.5V

REF

RESET

+5V

TCXO

14.85 MHz

U28D

O/L

J11

LEDS

DC POWER

(J1-25)

ENABLE

CR31

LED

CR33

FLASHER

(RTS)

CR32

CR33

CR32

CR31

R168

TRANSMIT DEV ADJ

(J6-18)

MODEM ENABLE

FILTER

TX AUDIO INPUT

U28B

U28C

U26

U15Z

(J1-9)

TX AUDIO

LOOPBACK

(J6-24)

MODEM TX AUDIO

BIAS

U40U33

AMP

ANTENNA SWITCH

XMI

DIRECTIONAL COUPLER

ANTENNA

CONNECTOR

MODUL

HYBRID

POWER

R69

12)

(J7-

FWD PWR

REFL PWR

U44

ADJUS

POWER

(J7-

VDC

U13

VDC

2.5

VDC

(J1-12)

RADIO

ENABLE

+13.5 V

U19

PTT

(J6-9)

(J1-16)

(J1-14)

MODEM PTT

Figure 5-1.MDS 4310 Transceiver Block Diagram

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-7/8

CHAPTER 6—TROUBLESHOOTING

If difficulties are experienced with the radio system, the steps outlined below can help isolate the faulty component. For specific instructions on performing the tests or adjustments recommended in this chapter, refer to Chapter 4—Field Tests and Adjustments. For instructions on using the Hand-Held Terminal (HHT), refer to Chapter 3—Programming and

Diagnostics.

Troubleshooting assistance is also available from Microwave Data Systems in Rochester, NY (Telephone No. (716) 242-9600). Please have the complete model number and serial number of the transceiver ready when calling for assistance. Refer to the inside back cover of this manual for more information on obtaining factory assistance.

UNIT DOES NOT TRANSMIT OR RECEIVE

1. Power Supply Evaluation a. Check for + 13.8 Vdc at transceiver’s primary power connector. b. Check the in-line fuse in the power cable assembly; if defective, replace with

type 3AG, 3 A fuse.

c. Check for continuity of plug-in fuse F1 (4A/Fast Blo) on the transceiver

motherboard. If it is blown, check for reverse polarity or excessive voltage on primary power leads. When the problem has been corrected, replace the fuse.

2. Antenna System Evaluation a. Check antenna feedline and connections. VSWR should be no higher than 1.5:1.

Higher VSWR values usually will not prevent the radio from functioning, but may degrade system performance.

3. Operating Frequencies Review a. Check the transmit/receive frequencies and other radio operating parameters

using HHT or PC terminal.

UNIT RECEIVES, BUT DOES NOT TRANSMIT

1. PTT Circuit Evaluation a. Check keying signal being supplied by RTU. Measure keyline input at DB-25

INTERFACE connector; either Pin 14 or 16 of this connector should be activated.

Alternate—Pin 4 of the INTERFACE connector.

b. Apply + 5 Vdc to Pin 14 (PTT), of the DB-25 INTERFACE connector, or a ground

to Pin 16

c. On modem-equipped radios, check the DB-25

RTS (Pin 4) and CTS (Pin 5) signals.

d. Key transmitter with HHT using the KEY command.

Continued on next page.

PTT of the DB-25 connector. The transceiver should key.

INTERFACE connector for proper

MDS 05-2415A01, Rev. A 6-1

2. Transmitter Power Measurement a. Measure transmitter power output at the ANTENNA connector with an in-line

wattmeter or a service monitor. It should not exceed 5 watts.

3. Transmit Modulation Evaluation a. Check to see that transmit audio connections are properly made. b. Check transmitter deviation and adjust, if necessary.

4. Transmit Frequency Measurement a. Check transmit carrier frequency with a service monitor or frequency counter

(± 0.000015% accuracy).

UNIT TRANSMITS, BUT DOES NOT RECEIVE

1. Receive Audio Evaluation a. Check for receive audio on Pin 11 of the DB-25 b. Check for proper receive frequency programming using HHT or PC terminal. c. Check that RUS line (Pin 10 of DB-25) goes high with a received signal.

2. Interface Functions—With Diagnostics Board Installed a. Check power supply voltage ( b. Check 8 volt regulator ( c. Check PLL VCO lock voltage ( d. Check RSSI voltage ( e. Check power output (

RSSI). KEY & FPWR).

SV).

VR).

LV).

f. Check programmed transmit and receive frequencies (

INTERFACE connector.

FRQ).

UNIT RECEIVES AND TRANSMITS, BUT SYSTEM PERFORMANCE IS POOR

1. Transmitter Evaluation a. Check transmit carrier frequency with a service monitor or frequency counter

(± 0.000015% accuracy).

b. Check transmitter modulation (≈2.5 kHz). c. Check RF output power level. It should not exceed 5 watts.

2. Receiver Evaluation a. Check receive 12 dB SINAD sensitivity at Pin 11 of DB-25 connector

(–117 dBm/0.3 µV).

b. Check audio output level. c. Check squelch threshold level. Squelch should open at a level greater than

–120 dBm

d. Check Master Station received signal strength using the HHT and the

RSSI

command, or measure the DC voltage at Pin 21 of the INTERFACE connector. (See Figure 2-4 to interpret the DC signal level in dBm.)

6-2 TROUBLESHOOTING MDS 05-2415A01, Rev. A

3. Antenna System Evaluation a. Inspect antenna for damage; the feedline for loose, shorted or waterlogged

connections.

b. Check forward and reflected power at

ANTENNA connector of transceiver using

in-line wattmeter (VSWR should be less than 1.5:1).

4. Interface Functions Evaluation a. Check for secure interface connections at the RTU and at the transceiver. b. Check the RTS/CTS delay setting—it should be normally be set to a minimum

of 10 ms.

c. Check to see if data is lost at beginning or end of transmission. If lost at

beginning, suspect problem with RTU keyline interface; if at end, squelch tail or soft carrier dekey timing problems.

d. If soft carrier dekey is needed, check for proper programming of delay with

HHT or PC terminal.

e. If noise from the squelch tail (closing) is interfering with the data flow, then

enable the Squelch Tail Eliminator function in the MDS 4310 using the ESTE command with the HHT. (Applies to analog systems only.)

f. Check for excessive length of the interface cable. This cable should be only as

long as necessary to reach the radio. If the length exceeds 50 feet, then an RS-232 to RS-422 Converter Assembly may be required. (MDS P/N 012358A01.)

MDS 05-2415A01, Rev. A TROUBLESHOOTING 6-3

This page intentionally blank

6-4 TROUBLESHOOTING MDS 05-2415A01, Rev. A

APPENDIX A—1200 BPS BELL 202T

COMPATIBLE MODEM

Optional System Equipment

Assembly P/N: 03-1815A01

INTRODUCTION

The 03-1815A01 modulator/demodulator (modem) was designed specifically for use with the MDS 4300 Series Transceivers, allowing it to be mounted within the transceiver housing into Option 1 jacks—J6 and J8. Figure A-1 shows an assembly drawing of the 1200 bps modem.

This modem is compatible with the Bell 202T standard and is normally used for a 1200 bitper-second (bps) data rate. It will track input data rates as low 50 bps. With this option mounted within the transceiver enclosure, the MDS 4310 Transceiver can still be programmed through the RS-232 connector, without the need to remove the housing cover.

J8J6

Figure A-1. 1200 bps Modem PC Board

SPECIFICATIONS

Current Drain: 20 mA from the primary power source Tone Frequencies: Mark: 1200 Hz, adjustable

Space: 2200 Hz, adjustable

Data Rates: 50–1200 bps Asynchronous

ALIGNMENT

Chapter 4—Field Tests and Adjustments contains alignment procedures for radios equipped with 1200 bps modems. The modem alignment consists of setting the Mark tone frequency (R2), Space tone frequency (R3), and the Receive Data Threshold (R25).

MDS 05-2415A01, Rev. A A-1

Microwave Data Systems MDS 4310 Operation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual