hf data modem · this typeface means... bold/bold a button, switch or connector ... qpsk quadrature...

H F R A D I O C O M M U N I C A T I O N S

R E F E R E N C E M A N U A L

HF Data Modem3012

No part of this manual may be reproduced, transcribed, translated into any language or transmitted in any form whatsoever without the prior written consent of Codan Limited.

NGT® is a registered trademark of Codan Limited

CALM® is a registered trademark of Codan Limited

Windows® is a registered trademark of Microsoft Corporation

Copyright 2001 Codan Limited

Codan part number 15-04104-EN Issue 2, November 2001

��Table of contents

1 About this manualStandards and icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Acronyms and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Circuit reference designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Unit multipliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

About this issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Associated documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

2 OverviewHigh Frequency Data Modem 3012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Channel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Types of data transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Transmission protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Physical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

3 InstallationUnpacking the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Additional equipment required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Terminal connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Transceiver connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Cables for connecting transceivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Installing the data modem system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Setting up the PC or terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Using a PC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Using a terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9

Setting the station address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

Confirming the station address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

Checking the operation of the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

Checking the connection between the transceiver system and the data modem . . . . . . . . . . . 3-11

Testing the data link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

HF Data Modem 3012 Reference Manual i

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4 Operating the data modemPowering up the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Indicators on the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Controlling the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Controlling the data modem using AT commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Switching to local command mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Returning to on-line mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Setting the unit address for polling stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Setting how calls are answered automatically . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Answering calls manually . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Terminating a link (hanging up) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Making selective call transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Making broadcast call transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Making group call transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

Enabling/disabling local data echo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Enabling/disabling remote data echo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Displaying remote station address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11

Storing station addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Dialling stored station addresses (quick dial) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Setting telephone compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

Changing the state of the DTR input line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

Displaying diagnostic information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Changing the response format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15

Saving data modem settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16

Resetting the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16

Resetting to factory defaults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16

Enabling/disabling data compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

Controlling data flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

Setting the modulation method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18

Displaying data modem product and version number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18

5 Setting up an NGT to operate with the data modemInstalling the data modem with an NGT transceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Mounting the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Connecting the data modem to the NGT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Setting up the NGT to operate with the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Setting up the serial port of the NGT using the handset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Setting up the serial port of the NGT using the system programmer . . . . . . . . . . . . . . . . . . . . 5-3

Setting up an NGT network to operate with the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Setting up automatic channel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

ii HF Data Modem 3012 Reference Manual

Table of contents

6 SpecificationsGeneral specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Environmental specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Physical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

7 How the data modem worksTechnical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

How the DSP Modem PCB works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Digital signal processor and CoDec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Logic and interfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Throughput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

How the User Connector PCB works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Transceiver interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Serial ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

8 Maintenance and fault findingAdjustments and routine maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

PCBs and units available as replacements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

PCB removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

Safety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

Fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

If technical assistance is required... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

Basic fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Advanced fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

What you need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Dismantling the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

Fault finding the power supply in the data modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

Testing the HF subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9

9 Drawings

Appendix A—AT commandsSummary of AT commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Summary of AT commands to display S-registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6

Index

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iv HF Data Modem 3012 Reference Manual

��List of figures

Figure 3-1: Rear panel of HF Data Modem 3012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Figure 3-2: Example installation setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Figure 3-3: Connection diagram for the transceiver system and data modem . . . . . . . . . . . . . 3-11

Figure 8-1: Exploded view of HF Data Modem 3012. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6

HF Data Modem 3012 Reference Manual v

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vi HF Data Modem 3012 Reference Manual

��List of tables

Table 3-1: Pinouts for the Terminal connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Table 3-2: Pinouts for the Transceiver connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Table 3-3: Cables used for Codan transceivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Table 4-1: Operational status as indicated by the LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Table 4-2: Response codes for the HF Data Modem 3012 . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15

Table 5-1: Settings for ALE/CALM, Codan Selcall and Voice Only networks operating with an HF Data Modem 3012 5-4

Table 8-1: Replacement PCBs and units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

Table 8-2: Customer service contact numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

Table 8-3: Basic fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5

Table A-1: AT commands for the HF Data Modem 3012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Table A-2: AT commands for the HF Data Modem 3012 S-registers . . . . . . . . . . . . . . . . . . . A-6

HF Data Modem 3012 Reference Manual vii

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viii HF Data Modem 3012 Reference Manual

��1 About this manual

This reference manual is for installation technicians and operators of the High Frequency Data Modem 3012.

The manual has nine chapters and one appendix:

Chapter 1 About this manual—lists all terms, abbreviations and units used in this manual

Chapter 2 Overview—contains a general description of the data modem

Chapter 3 Installation—describes how to install the data modem

Chapter 4 Operating the data modem—describes how to operate the data modem

Chapter 5 Setting up an NGT to operate with the data modem—provides specific information for operating the data modem with a Codan NGT transceiver

Chapter 6 Specifications—contains the specifications for the data modem

Chapter 7 How the data modem works—provides a brief technical description of how the data modem works

Chapter 8 Maintenance and fault finding—describes how to maintain the data modem, and the possible causes of faults

Chapter 9 Drawings—contains the drawings referred to in this manual

Appendix A AT commands—lists all the AT commands that may be used with the data modem

There is an index at the end of this manual.

HF Data Modem 3012 Reference Manual 1-1

About this manual

Standards and icons

The following standards and icons are used in this manual:

This typeface Means...

BOLD/Bold a button, switch or connector

Bold a command that you enter or keyboard key that you press

Courier a segment of text that is taken directly from a computer screen

Italics a cross-reference or text requiring emphasis

This icon Means...

a warning—your actions may cause harm to yourself or the equipment

a caution—proceed with caution as your actions may lead to loss of data, privacy or signal quality

a note—the text provided next to this icon may be of interest to you

� a step to follow

1-2 HF Data Modem 3012 Reference Manual

About this manual

Definitions

Acronyms and abbreviations

Acronym Means…

ACE asynchronous communications element

ALC automatic level control

ALE automatic link establishment

ARQ automatic repeat request

ASCII American standard code for information interchange

AT attention

CALM Codan automated link management

CD carrier detect

CICS computer interface command set

CoDec coder/decoder

CPU central processing unit

CTS clear to send

DC direct current

DSP digital signal processor

DSR data set ready

DTE data terminal equipment

DTR data terminal ready

EEPROM electrically erasable programmable read only memory

EPROM erasable programmable read only memory

ESR equivalent series resistance

FIFO first-in first-out

GND ground

HF high frequency

IC integrated circuit

I2C inter integrated circuit

I/O input/output

LED light emitting diode

NC not connected


About this manual

NSP NGT System Programmer

OC open collector (active low)

PC personal computer

PCB printed circuit board

PLCC plastic J-leaded chip carrier

p−p peak to peak

PTT press to talk

QPSK quadrature phase shift keying

RAM random access memory

RTS request to send

RxD receive data

SRAM static random access memory

SSB single sideband

TSOP thin small outline package

TTL transistor−transistor logic

TxD transmit data

Acronym Means…


About this manual

Glossary

Term Description

ACE A peripheral semiconductor device used to provide additional serial interfaces to a microcontroller or digital signal processor.

AT commands Set of commands commonly used to operate many types of modems.

CHIRP A robust signalling protocol used by the data modem during link establishment.

coder/decoder A device combining analog to digital and digital to analog converters.

data terminal equipment

An RS232-related term indicating a personal computer or terminal.

digital signal processor

A microprocessor-like device that is designed to quickly process high volume digital data streams.

effective throughput

Average data transfer rate taking the effects of data compression into account. For example, if system throughput is 1000 bps and data compression reduces data size by 50%, the effective throughput is 2000 bps.

first-in first-out A buffer used in serial communications devices to reduce CPU overheads.

frequency offset Difference between the frequencies being used by a sending and a receiving modem station. The variation is due to changes in temperature, variations in power supply voltage or the aging of components.

signalling rate Rate at which data is transmitted (this remains constant at 2400 bps).

throughput Average data transfer rate between stations (this varies with different channel conditions).

transceiver The unit that converts audio signals to radio frequencies that may be transmitted on air, and that converts the radio frequencies it receives into audio signals. In this manual, when referring to the NGT, transceiver equates to the RF unit.

transmission protocol

Method used by a modem to transmit and receive information.


About this manual

Circuit reference designations

Units

Abbreviation Designation

C capacitor

D diode—small signal and power

IC integrated circuit, thick film hybrid etc

L inductor

S switch

TP test point

V semiconductor (not including small signal and power diodes)

Measurement Unit Abbreviation

Current ampere A

Distance metre m

Frequency hertz Hz

Impedance ohm Ω

Mass gram g

Power watt W

Rate of data transfer baud baud

Rate of data transfer bits per second bps

Temperature degrees Celsius °C

Temperature (Absolute) kelvin K

Time hour hr

Time second s

Voltage volt V


About this manual

Unit multipliers

Unit Name Multiplier

n nano 10–9

µ micro 10–6

m milli 10–3

d deci 10–1

k kilo 103

M mega 106

G giga 109


About this manual

About this issue

This is the second issue of the HF Data Modem 3012 Reference Manual.

Associated documents

Other publications associated with the HF Data Modem 3012 are:

• 9102 Fax and Data Controller Software User Guide (Codan part number 15-04039)

• NGT System Programmer User Guide (Codan part number 15-04105-EN)

• NGT AR Transceiver User Guide (Codan part number 15-04118-EN)

• NGT SR Transceiver User Guide (Codan part number 15-04096-EN)

• NGT AR, SR and VR Transceiver Reference Manual (Codan part number 15-04099-EN)


��2 Overview

This chapter describes the features of the HF Data Modem 3012. It includes:3434

• a brief functional description of the data modem (2-2)

• a brief physical description of the data modem (2-5)


Overview

High Frequency Data Modem 3012

Introduction

The HF Data Modem 3012, when combined with the appropriate HF SSB transceiver and computer terminal, provides error-free transmission and reception of data on an HF channel. It is particularly useful for long-range communications in remote areas where existing communications are poor or non-existent.

The data modem operates at 12 V DC in fixed base and mobile installations. It incorporates data compression to boost effective throughput and is easily integrated with Codan voice and signalling networks.

A typical HF Data Modem 3012 station comprises:

• HF Data Modem 3012

• Codan ‘data-capable’ transceiver

• power supply

• computer terminal with appropriate communications software

• antenna system

The data modem is supplied with Codan 9102 Fax and Data Controller Software. This software provides easy operation of the data modem for simple messaging, chat and file transfer between data stations. Alternatively, the data modem may be controlled using standard AT commands from a terminal. Virtually any software that operates on standard telephone modems will operate over HF via the AT commands.

The data modem is able to send email over HF with other third party email software.

Channel selection

HF channels may be manually selected using the transceiver or the data modem.

If a data call is sent while the NGT transceiver is scanning a CALM network, the transceiver automatically selects the channel using the CALM network.

Types of data transmission

There are three types of data transmission:

• selective call

• group call

• broadcast call

Selective calls guarantee error-free transmission, while group and broadcast calls may be subject to errors under poor channel conditions.


Overview

Selective call

A selective call allows transmission of data to a single, specific station.

Once a link has been established using a selective call, data may be sent in both directions between the two stations.

The data modem has been optimised for data transfer, however interactive chat mode is possible between the two stations.

Group call

A group call allows transmission of data to as many as 99 stations at one time. Therefore, it is useful for sending a message to a number of stations without having to establish a separate link with each station.

Broadcast call

A broadcast call allows transmission of data to all stations that are ready and able to communicate on the channel selected.

Transmission protocol

Data link establishment

Before data can be transmitted to a receiving station, the data modem must establish a link. This is done using a robust signalling protocol that determines the address of the receiving station and the frequency offset between the sending and receiving stations.

Once the link has been established, control is transferred to a high speed data transmission protocol to send the data.

The link establishment protocol is less sensitive to channel conditions than the high speed signalling protocol. This means that under some channel conditions, link establishment may succeed but data transmission may fail.

Selective transmissions

Selective transmission involves a two-way communication process between two data modem stations. Data is transferred in information packets. Every packet contains error detection information to let the receiving station know if the data was correctly received.

Notification of any corrupt transmissions is sent back to the sending station and re-transmitted in the next information packet.


Overview

Group and broadcast transmissions

Group and broadcast transmissions involve a one-way communication process used to send data to multiple data modem stations. During a transmission, a receiving station is unable to respond to the transmitting station.

The transmitting station sends information packets in the same way as in a selective transmission, but all packets are sent four times. After the transmission, a receiving station will have four copies of each packet of information from which to extract correct data. This is sufficient for most conditions. However, errors may occur under poor channel conditions, resulting in blocks of missing data.

For this reason, it is recommended that only text messages are sent in group and broadcast transmissions, as one error would be sufficient to make an encrypted or compressed message indecipherable.


Overview

Physical description

General

The HF Data Modem 3012 is housed in a diecast aluminium chassis, containing two PCBs:

• DSP Modem PCB (main PCB)

• User Connector PCB

The User Connector PCB supports the connectors mounted on the rear panel. The two boards are linked by three internal wiring looms.

Indicators

The data modem has a LED indicator and a Throughput indicator on the front of the unit. The LED indicator comprises one multi-colour LED. The Throughput indicator comprises 10 red LEDs that form a bar graph of the potential data throughput.

Connectors

The data modem has two connectors on the rear panel—a Terminal connector and a Transceiver connector (see Figure 3-1 on page 3-4).

The data modem receives DC power from the transceiver via the Transceiver connector.


Overview



��3 Installation

This chapter describes how to install the HF Data Modem 3012. It includes:

• unpacking the data modem (3-2)

• additional equipment required (3-3)

• connectors (3-4)

• cables for connecting transceivers (3-6)

• installing the data modem system (3-7)

• setting up the PC or terminal (3-9)

• setting the station address (3-10)

• checking the operation of the data modem (3-11)


Installation

Unpacking the data modem

Remove the data modem and supplied cabling from their packaging. Check that the following items are present:

• HF Data Modem 3012 (Codan part number 08-05877-001)

• computer cable (Codan part number 08-05086-001)

• earth braid (Codan part number 08-04515-001)

• HF Data Modem 3012 Reference Manual (Codan part number 15-04104-EN)

• four rubber feet for the lower cover of the data modem (optional) (Codan part number 30-11208-000)

• serial port adaptor 9 to 25-way (Codan part number 60-00098-596)

• 9102 Fax and Data Controller Software (on 3½" floppy disk, Codan part number 90-20504-001)

Inspect each item to ensure it is not damaged. If you notice any damage, return the damaged item intact to Codan for replacement. Failure to do so may result in any warranty being void.


Installation

Additional equipment required

The following additional equipment is required to set up an HF Data Modem 3012 station:

• Codan transceiver configured for continuous data operation (includes a fan Option F; pre–NGT transceivers require Option D)

• AC power supply unit

• antenna system

• PC with suitable communication software, or a terminal

• transceiver interconnect cable (see Table 3-3 on page 3-6)


Installation

Connectors

The data modem has two connectors on the rear panel—the Terminal connector and the Transceiver connector.

Figure 3-1: Rear panel of HF Data Modem 3012

Terminal connector

The 9-pin D-type Terminal connector is used to connect the data modem to a data terminal or PC.

The CTS and RTS lines provide hardware flow control between the data modem and the terminal or PC.

Table 3-1: Pinouts for the Terminal connector

Pin No. Name In/Out Signal Description

1 NC - Not connected

2 RxD In Receive serial data

3 TxD Out Transmit serial data

4 CD Out Carrier detect

5 GND - Signal ground connected to case

6 Reset In Modem reset input

7 RTS Out Request to send (flow control)

8 CTS In Clear to send (flow control)

9 NC - Not connected


Installation

Transceiver connector

The 15-pin D-type Transceiver connector is used to connect the data modem to the transceiver. This interface also supplies switched DC power from the transceiver to the data modem.

Table 3-2: Pinouts for the Transceiver connector

Pin No. Signal Description

1 +12 V power supply input

2 +12 V power supply input

3 Serial control data output (TTL)

4 Not connected

5 QUIET output, +12 V when in data mode

6 Busy output (OC)

7 PTT output (OC)

8 Audio output (3 V p−p max)

9 Ground

10 Ground

11 Scan input

12 Spare input

13 BUSY input

14 Serial control data input (TTL)

15 Audio input (4 V p−p max)


Installation

Cables for connecting transceivers

The cables required to connect the data modem to the Codan transceiver depend on the type of transceiver used and the length of cable required. These cables are shown in the table below.

Table 3-3: Cables used for Codan transceivers

Transceiver Codan part number of cable

NGT AR/SR/VR 08-05712-001 (1 m length)08-05712-006 (6 m length)

93XX 08-05014-001 (1 m length)


Installation

Installing the data modem system

To install the equipment for the data modem system:

� Position the AC power supply with enough space behind it to ensure the ventilation fan operates effectively.

� Place the transceiver on top of the power supply (see Figure 3-2).

� Place the data modem on top of the transceiver.

� Connect the DC power cable from the transceiver to the power supply unit.

� Connect the earth strap to the earth connections (indicated by ) between the transceiver and the data modem.

Figure 3-2: Example installation setup

� Connect the appropriate cable (see Table 3-3 on page 3-6) between the Transceiver socket on the data modem and the socket on the transceiver listed below:

� Connect the computer cable (Codan part number 08-05086-001) between the Terminal socket on the data modem and the serial port of the terminal or PC.

If the earth strap is not connected between the transceiver and the data modem, there may be excess noise on the channel.

Transceiver Socket

NGT (GPIO)

93XX GP

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Installation

� Connect both the power supply and the terminal or PC to a mains power socket.

� Connect the transceiver to the antenna system.

� Switch on the power supply and the transceiver.

All the LEDs of the Throughput indicator illuminate briefly, then the LED illuminates steady green.

Ensure the correct mains voltage has been selected for the power supply and the terminal or PC.


Installation

Setting up the PC or terminal

Using a PC

When using the 9102 Fax and Data Controller Software provided with the data modem on a PC, the relevant PC settings are set up automatically when the software is installed. For the minimum PC requirements, see Chapter 3, Before starting 9102 in the 9102 Fax and Data Controller Software User Guide.

Using a terminal

If you are using a terminal connected to the data modem instead of the 9102 Fax and Data Controller Software on a PC, the terminal must be set as follows:

• 9600 baud

• 8 data bits

• no parity

• 1 stop bit

• hardware handshaking (RTS/CTS signals)

If you are running the 9102 Fax and Data Controller Software in Windows® under the MS-DOS operating system, there may be data loss when the data modem is working.


Installation

Setting the station address

The station address must be set for the data modem station. The station address is the number other stations use to contact this station.

The station address may be set either by using the 9102 Fax and Data Controller Software provided with the data modem, or by using AT commands via a terminal connected to the data modem.

If you are using the 9102 software, refer to the 9102 Fax and Data Controller Software User Guide for instructions.

To set the station address using AT commands:

� If the data modem is in on-line mode, switch to local command mode (see page 4-5, Switching to local command mode).

� On the terminal keyboard, type:

AT&I=nnnnnn where nnnnnn is the station address (up to six numbers).

Do not set the station address to any number ending in 00, otherwise the selective call feature will not work.

� Press Enter.

The terminal responds with OK.

Confirming the station address

To confirm the current data modem station address using AT commands:

� On the terminal keyboard, type AT&I?.

� Press Enter.

The terminal responds with the current station address followed by OK.


Installation

Checking the operation of the data modem

Checking the connection between the transceiver system and the data modem

Prior to testing the data link by running the 9102 Fax and Data Controller Software, the transceiver must be powered and have a connection between the 15-way port of the Junction Box 2030 or Desk Console 2040 and the Transceiver port of the data modem (see Figure 3-3).

Figure 3-3: Connection diagram for the transceiver system and data modem

To check the connection:

� Connect the COM port from the PC to the Terminal connector on the data modem.

� Switch on the PC.

� Configure the COM port connected to the data modem to 9600 baud, no parity, 8 data bits and 1 stop bit.

� Power up the transceiver system.

� From the terminal program, type ATE1 and then press Enter.

If the OK response is displayed on the PC screen (possibly with other information), exit the terminal software as the correct connection is in place.

The PC must have terminal software installed, e.g. Microsoft Windows HyperTerminal .

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Installation

Testing the data link

To test the data link:

� Switch on the transceiver and data modem.

� Switch on the PC that is connected to the Terminal connector on the data modem.

� Start up the 9102 Fax and Data Controller Software.

The PC should display Setting up Modem while a connection is being made between the PC and the data modem.

If the software cannot communicate with the data modem, check the serial port settings from the Options menu, Serial Port Options.

If the settings are correct, check the cable connections.

� From the Options menu, select Modem Options.

� Enter your station address in the My Station Address field (maximum of six digits).

� Click OK.

Sending a selcall to another HF data system

To send a selcall:

� From the Call Menu, select Selective and Group.

� Enter the address of the station you want to call in the Station Address field.

� Click OK.

The PC should display Connecting while establishing a connection to the called station. When a successful connection has been made, the message changes to On Air.

Sending a text message

To send a text message:

� Type a text message in the Sending window.

As the message is sent, the contents are displayed in the Sent window.

The data modem is now ready for operation.


��4 Operating the data modem

This chapter describes how to operate the HF Data Modem 3012. It includes:1212

• powering up the data modem (4-2)

• modes of operation (4-3)

• controlling the data modem (4-4)


Operating the data modem

Powering up the data modem

The data modem receives its DC power supply from the attached transceiver. Therefore, if power is on to the transceiver, and the data modem is connected to the transceiver correctly (see Chapter 3, Installation), the data modem will be powered up.

Indicators on the data modem

The data modem has a LED indicator on the front of the unit. The operational status of the data modem is indicated by the colour of the LED and its flash rate, as described in the table below.

The Throughput indicator comprises 10 red LEDs that form a bar graph of the potential data throughput. For modulation over 16 channels (AT&M=5), each LED in the indicator represents approximately 100 bps of data throughput. The LEDs illuminate accumulatively, e.g. five LEDs illuminated represents approximately 500 bps of data throughput.

Table 4-1: Operational status as indicated by the LED

Colour Flash rate Operational status

Green Not flashing Power on, idle

Green Fast Receiver, establishing call

Green Slow Receiver, call established

Orange Fast Sender, establishing call

Orange Slow Sender, call established

Red Not flashing Non-volatile memory failure



Modes of operation

The data modem has two modes of operation:

• local command mode

• on-line mode

The data modem enters local command mode automatically when it is powered up. This mode allows the operator to change control parameters.

The data modem automatically enters on-line mode whenever a successful link is established between it and one or more other modems. The data modem remains in on-line mode until the link is terminated, the power is turned off then on again, or a special command (called an escape command) is received to switch the data modem back to local command mode (see page 4-5, Switching to local command mode).

Your data modem must be in local command mode to perform any AT commands sent from the PC or terminal.



Controlling the data modem

There are no operator controls on the data modem. Its operation is controlled using AT commands via the serial port of a PC or terminal. AT commands can be automated by appropriate PC software. Alternatively, terminal software such as HyperTerminal© for Windows® or 9102 Fax and Data Controller Software may be used to control the data modem.

For instructions on controlling the data modem using a PC running the 9102 Fax and Data Controller Software, refer to the 9102 Fax and Data Controller Software User Guide.



Controlling the data modem using AT commands

AT commands are a set of commands used to operate many types of commercially available modems.

The data modem must be in local command mode before you may use AT commands.

All AT command lines must start with the characters AT. Commands may be typed in upper or lower case and all command lines must be executed by pressing Enter. Any spaces on the command line are ignored when the command is processed. Several AT commands may be grouped together up to a maximum length of 40 characters.

While entering AT commands, you may use the backspace key to correct mistakes on the current entry line. However, the AT at the beginning of the command line must be typed in correctly the first time without using the backspace key.

The data modem switches to on-line mode automatically whenever a successful link is established between it and one or more other modems.

Switching to local command mode

Before you may use AT commands, the data modem must be in local command mode.

To switch from on-line mode to local command mode:

� Wait at least one second after the last character of a message has been sent.

� Type +++ (the escape characters).

� Wait at least one second before entering another character.

When the data modem switches to local command mode, OK is displayed on the terminal.

A complete set of AT commands that may be used with the data modem are in Appendix A of this manual. However, the remainder of this chapter describes the most commonly used commands.

The data modem defaults to local command mode when it is first powered up.

The time delay either side of the escape characters is to stop the three escape characters switching the data modem to local command mode if they are received as part of a data stream.



Changing the escape characters

The escape characters (+++) used to switch from on-line mode to local command mode may be changed if necessary.

To change the escape characters:

� Type AT&E= followed by the ASCII value of the character you wish to use for the escape sequence.

For example, AT&E=42 would set the escape characters to ***.

� Press Enter.

Returning to on-line mode

The data modem automatically enters on-line mode whenever a successful link is established between it and one or more other modems.

However, to manually switch the data modem from local command mode to on-line mode:

� Type ATO (letter ‘O’, not zero) and press Enter.

Setting the unit address for polling stations

If your base station polls several remote stations for data, it may be useful to terminate the poll to the remote station early if it has no data to transmit. This is done by the remote station sending an abort signal. When a remote station has data to send, it could be set up to receive all calls (see page 4-7, Enabling automatic answering of calls). When the station does not have data to send, it could be set up to reject all calls from a data modem with a unit address (see page 4-7, Enabling automatic rejection of calls). If the base station sets its unit address to 1 prior to polling each remote station, then the remote station immediately sends an abort signal if it has no data to send.

To set a unit address:

� Type AT&U=nn where nn is between 0 and 15, then press Enter.



Setting how calls are answered automatically

The automatic answering feature of the data modem applies to both answering and rejecting calls. When a remote data modem station attempts to call your data modem station, RING is displayed on the terminal to indicate the incoming call. Your data modem will not respond to the call until an answer/reject command is sent from the terminal to your data modem.

You can set up the data modem to answer the call automatically, or wait until you manually answer the call.

Enabling automatic answering of calls

To enable the data modem to answer the call automatically:

� Type AT&A=1 and press Enter.

Incoming calls are now answered automatically after one ring, then the data modem waits for a carrier signal.

The data modem automatically switches to on-line mode once the link has been established.

Enabling automatic rejection of calls

Calls may be automatically rejected in two ways. You can set the data modem to reject calls from another data modem with a unit address that is greater than zero, or you can set the data modem to reject all calls. For information on how to set a unit address, see page 4-6, Setting the unit address for polling stations.

To reject calls from a data modem with a unit address that is greater than zero:


The data modem sends an abort to the other data modem as soon as it receives a unit address that is greater than zero.

To reject all calls:


The data modem sends an abort to the other data modem immediately.

Do not send any characters until the data modem responds to the terminal with CONNECT, otherwise the data modem aborts link establishment.

An HF link is terminated when one of the following occurs:

• the hang up command is issued (see page 4-8, Terminating a link (hanging up))

• the station at the other end of the link hangs up

• the link fails due to poor quality or no response from the other station



Disabling automatic answering of calls

The automatic answering feature of the data modem applies to both answering and rejecting calls.

To disable the automatic answering feature of the data modem:


Incoming calls now need to be answered manually (see page 4-8, Answering calls manually).

Displaying the answer mode setting

To display the status of the automatic answering feature:

� Type AT&A? and press Enter.

Answering calls manually

The answer command must be used to answer a call manually if the automatic answering feature of the data modem has been disabled (see page 4-8, Disabling automatic answering of calls).

To manually answer a call:

� Type ATA and press Enter.

The data modem immediately answers the call and waits for a carrier signal.

The data modem automatically switches to on-line mode once the link has been established.

Terminating a link (hanging up)

An HF link is not terminated until the hang up command is issued.

To terminate the HF link at both ends:

� Type ATH or ATH0 and press Enter.

Do not send any characters until the data modem responds to the terminal with CONNECT, otherwise the data modem aborts link establishment.

The ATH command may take up to 30 seconds to complete while both stations disconnect from the link.



To ignore all incoming calls:

� Type ATH1 and press Enter.

To terminate the HF link when all data in the buffers has been transmitted:


To terminate the HF link immediately (all data in the buffers is lost):


To go on line, and when the user stops typing data and all data has been transmitted, hang up:

� Type ATO1 (letter ‘O’, not zero) and press Enter.

Making selective call transmissions

A selective call transmission is the fastest and most reliable way to send data to one station. Selective call transmissions are error-free and data compression is available (see page 4-17, Enabling/disabling data compression).

To make a selective call transmission:

� Type ATD followed by the address of the station you want to call, then press Enter.

The data modem waits for a response from the remote data modem.

If a response is detected and the link is established successfully, CONNECT is displayed on the terminal and the data modem switches to on-line mode.

If a response is detected but the link is not established or either data modem aborts the call, NO CARRIER is displayed on the terminal.

If no response is detected within the time-out period (approximately two minutes), the data modem aborts the call and NO ANSWER is displayed on the terminal.

Calls can be received again by entering ATH or by making a call to another station.

The remote data modem is not informed that the connection has been lost. Control returns to the operator immediately.



Making broadcast call transmissions

A broadcast call transmission enables you to send data to all stations that are ready and able to communicate on the transmission channel.

The broadcast call transmission establishes a one-way link to the receiving stations. All broadcast call transmissions are sent four times by the data modem. This provides reliable reception without excessively degrading the transmission speed.

To make a broadcast call transmission:

� Type ATD and press Enter.

When the data modem is ready to send data, CONNECT is displayed on the terminal and the data modem switches to on-line mode.

Making group call transmissions

A group call transmission enables you to send data to up to 99 stations. These stations must be ready and able to communicate on the transmission channel.

As with a broadcast call transmission, the group call transmission establishes a one-way link to the receiving stations, and the transmission is sent four times to ensure reliable reception.

To make a group call transmission:

� Type ATD followed by the address of the stations you want to call, replacing the last two digits with 00.

For example: entering the address 123400 sends to all stations with addresses between 123401 and 123499 inclusive.

� Press Enter.

When the data modem is ready to send data, CONNECT is displayed on the terminal and the data modem switches to on-line mode.

Data compression cannot be used with broadcast call transmissions.

Data compression cannot be used with group call transmissions.



Enabling/disabling local data echo

Enabling local data echo means that data sent by the local data modem is echoed on the local terminal screen during the transmission.

To enable local data echo:

� Type ATL1 and press Enter.

To disable local data echo:

� Type ATL0 and press Enter.

Enabling/disabling remote data echo

Enabling remote data echo means that data received by the remote data modem is echoed on the local terminal screen during the transmission.

To enable remote data echo:

� Type ATR1 and press Enter.

To disable remote data echo:

� Type ATR0 and press Enter.

Displaying remote station address

To display the address of the remote station to which the local station was last connected or is currently connected:

� Type AT&R? and press Enter.

Data is echoed on the local terminal screen even if it has not been successfully transmitted to the remote station.

Don’t enable both the local and the remote data echo. This results in data echoed back twice and at different times.

Data is echoed on the local terminal screen only after the remote station has successfully received the transmission.

Don’t enable both the local and the remote data echo. This results in data echoed back twice and at different times.



Storing station addresses

Up to four station addresses may be stored for quick dialling, if required.

To store a station address:

� Type AT&Z0= followed by the first station address you want to store and press Enter.

The entered station address is stored as quick dial number 0.

� Type AT&Z1= followed by the second station address you want to store and press Enter.

The entered station address is stored as quick dial number 1.

� Repeat for the remaining two quick dial numbers (2 and 3).

Dialling stored station addresses (quick dial)

To dial one of four stored quick dial station addresses:

� Type ATDS= followed by the quick dial number of the station you want to dial (between 0 and 3) and press Enter.

Setting telephone compatibility

When telephone compatibility mode is turned on, the behaviour of the data modem approximates a standard telephone modem more closely, allowing easier integration into computer-controlled applications.

Telephone compatibility mode has the following effects:

• If the ATA command has been used, ATX is 3, 4 or 5 and the H/W busy input signal is active, then the data modem responds with NO CARRIER instead of BUSY.

• If the ATD command has been used, ATX is 2, 4 or 5 and there is HF modem traffic (carrier) on the current channel, then the data modem responds with NO DIALTONE instead of BUSY.

• Responses to AT commands have an extra linefeed and carriage return (Enter) after them.

• Responses to each AT command are delayed by 120 ms after receipt of Enter at the end of the AT command.

• The ATS0 command is used to switch the automatic answering/rejection of calls on or off (rejection may be based upon the unit address of the sending data modem).

• The ATL command is disabled to provide compatibility with the loudspeaker volume on other modems. Use the ATF command to change the local echo setting.

• Any unknown commands are responded to with OK instead of ERROR. This does not include commands with illegal values, which still generate the response ERROR.



To enable telephone compatibility mode:

� Type ATB1 and press Enter.

To disable telephone compatibility mode:

� Type ATB0 and press Enter.

Changing the state of the DTR input line

You can instruct the data modem how to respond to changes in the state of the DTR input line.

To instruct the data modem to ignore the DTR input:

� Type AT&D=0 and press Enter.

To instruct the data modem to change to local command mode if it is currently on line and the DTR input goes low:


To instruct the data modem to hang up when the DTR input goes low and not answer calls until it goes high again:


To instruct the data modem to perform a reset if the DTR input goes low:


To instruct the data modem to connect to the station address stored in AT&Z0=dddddd when the DTR input goes high:


If the link fails, a reconnection is attempted until the link is established. If the DTR input goes inactive, the data modem hangs up.

The DTR input line only behaves as described above when the hardware link X2 is open (default). (X2 is located on the edge of the User Connector PCB, next to connector P6.) When link X2 is closed, the data modem resets when the DTR input line becomes active.



Displaying diagnostic information

The warning level command instructs the data modem how much diagnostic information it should display in response to AT commands.

To instruct the data modem not to give reasons for error messages:

� Type ATW0 and press Enter.

To instruct the data modem to give reasons for error messages:


To instruct the data modem to show its status when connecting or disconnecting:


The following message are sent when a connection is made:

After the link terminates (i.e. after NO CARRIER), the terminal displays what caused it to stop.

To instruct the data modem to give reasons for error messages and to show its status when connecting or disconnecting:


Method : QPSK...

Channels :

Secure : YES or NO

Freq offset : Hz

or

CONNECT BCAST



Changing the response format

A response is information, an error message or an entry prompt that the data modem displays on the terminal.

Each response has a number and/or message attached to the code (see Table 4-2 below).

To display message responses:

� Type ATV1 and press Enter.

To display numeric responses instead of messages:

� Type ATV0 and press Enter.

Response codes

Response codes for the data modem are listed in the table below.

Table 4-2: Response codes for the HF Data Modem 3012

Code:Digit (ATV=0)

Code:Characters (ATV=1)

Description

0 OK Command line accepted and executed

1 CONNECT BCAST Broadcast connection

2 RING Ringing signal detected

3 NO CARRIER Carrier lost or not detected

4 ERROR Command line longer than 40 characters, or invalid command

5 – Not used

6 – Not used

7 BUSY HF channel in use

8 NO ANSWER No response from remote station

9 – Not used

10 CONNECT Selective connection

13 RINGING Attempting to establish link with remote station



Saving data modem settings

The data modem has the ability to store its current settings in non-volatile RAM.

After initial set up, every time the data modem is powered up or the reset command is used, the configuration of the data modem is restored from non-volatile RAM.

To view all non-volatile RAM settings:

� Type AT&V and press Enter.

To store current settings:

� Type AT&W and press Enter.

The saved configuration remains until another AT&W command is entered.

Resetting the data modem

The reset command is used to return all the settings of the data modem to the values that have been stored in the non-volatile RAM.

To reset the data modem:

� Type ATZ and press Enter.

Resetting to factory defaults

To return the data modem to factory default values:

� Type AT&F and press Enter.

To permanently store the factory defaults into non-volatile memory:

� Type AT&W and press Enter.

Your data modem will lose its self address.



Enabling/disabling data compression

The data modem can be instructed to use data compression for selective call transmissions if required. Data compression increases the effective throughput of the data modem.

To enable data compression for selective call transmissions:

� Type AT%C2 and press Enter.

To disable data compression for selective call transmissions:

� Type AT%C0 and press Enter.

Controlling data flow

The flow control command is used to instruct the data modem on the type of data flow control to use on the serial port. It applies to both local command mode and on-line mode.

To use the hardware flow control (RTS/CTS):

� Type AT&K=3 and press Enter.

To use no flow control:


To use software flow control (XON/XOFF):


Data compression may only be used for selective transmissions. At the start of a call, compression is automatically disabled if either station does not support it.

Software flow control should not be used when binary data transfers are in progress.



Setting the modulation method

The modulation method sets the way in which the data modem transforms the data onto a signal for sending. The modulation method affects the point of sending. If the receiving data modem is set at a modulation method other than that of the sending station, the modems use the best common modulation method.

For good signal conditions, 16 channels is the recommended setting. In poorer signal conditions you may achieve better results if you select to modulate over 4 channels, however this greatly increases the transmission time.

Secure modulation makes it difficult for other modems to eavesdrop on your transmission.

Interactive modulation improves response times for small amounts of data.

To set the modulation over 4 channels, not secure:

� Type AT&M=0 and press Enter.







To set the modulation over 16 channels, secure:


To set the modulation over 16 channels, secure, interactive:


Displaying data modem product and version number

To display the product version number and date of the data modem:

� Type ATI and press Enter.

To display the product identity:

� Type ATI1 and press Enter.


��

5 Setting up an NGT to operate with the data modem

This chapter describes how to set up a Codan NGT transceiver to operate with the HF Data Modem 3012. It includes:1414

• installing the data modem with an NGT transceiver (5-2)

• configuring the NGT to operate with the data modem (5-3)

• setting up automatic channel selection (5-5)


Setting up an NGT to operate with the data modem

Installing the data modem with an NGT transceiver

To install the HF Data Modem 3012 with a Codan NGT transceiver, follow the instructions in Chapter 3, Installation, and use the additional information below.

Mounting the data modem

The data modem is designed to stack on top of the NGT RF unit. Fit the four rubber feet supplied to the lower cover of the data modem before stacking the unit on the NGT.

However, if rigid mounting is necessary, the data modem may be mounted by the rear mounting flange with a front fixing bracket, or inside the existing NGT mobile mounting cradle (Codan part number 15-00136).

Connecting the data modem to the NGT

To connect the data modem to the NGT, use the NGT to data modem connector cable (Codan part number 08-05712-001 or 08-05712-006).



Setting up the NGT to operate with the data modem

To operate the data modem with the NGT, the 15-way serial port of the NGT and the networks used by the NGT must be set up as described below.

Setting up the serial port of the NGT using the handset

To set up the 15-way serial port of the NGT using the handset:

� Log in as an administrator and set locks off (see Chapter 9, Managing lists in the NGT AR, SR and VR Transceiver Reference Manual).

� From the Main Menu, scroll to Control and press the key to select it.

� Scroll to the RS232 15way Mode entry and hold the key to edit the setting.

� To set the 15-way mode, scroll to Fax/Data then press the key.

The display returns to the entry level.

� Scroll to the RS232 15way Speed entry and hold the key to edit the setting.

� To set the 15-way baud rate, scroll to 9600 then press the key.

The display returns to the entry level.

� Press the key to return to the Main Menu.

� Switch the transceiver off then on again.

Setting up the serial port of the NGT using the system programmer

To set up the 15-way serial port of the NGT using NSP:

� Load the profile from the transceiver (see Chapter 4, Working with profiles in the NGT System Programmer User Guide).

� From the View menu, select Preferences and set the access rights so the Admin Hidden and Locked settings are shown (see Chapter 15, Preferences in the NGT System Programmer User Guide).

� From the View menu, select Controls.

� Find the RS232 15way Mode setting, click on the down arrow and select Fax/Data.

� Find the RS232 15way Speed setting, click on the down arrow and select 9600.

� To store these settings as a profile, select Save As… from the File menu and save the file using an appropriate filename.

� Program the saved profile to the transceiver (see Chapter 4, Working with profiles in the NGT System Programmer User Guide).

� Switch the transceiver off then on again.

There are a large number of entries in the Control List. You can use the Find option to find this specific entry (see Chapter 4, Getting started in your NGT Transceiver User Guide).



Setting up an NGT network to operate with the data modem

The settings for a network operating with an HF Data Modem 3012 vary depending on the call system selected (see Table 5-1). These settings ensure that the NGT scans each channel long enough for the data modem to detect incoming signals. To program a network with these settings, see Chapter 4, Programming a network in the NGT AR, SR and VR Transceiver Reference Manual.

Networks for stations using different call systems

If you are using an NGT with an HF Data Modem 3012 in networks that consist of stations using different call systems, two networks must be configured—one for ALE/CALM and the other for Selcall or Voice Only (see Table 5-1).

ALE/CALM networks for sending data

If you are sending a data call while the NGT transceiver is scanning, the data modem selects the first ALE/CALM network in the list of scan-enabled networks. The networks in this list are in alphabetical order, so you should set up the ALE/CALM network on which you want to send data so that it appears first in the list of scan-enabled networks.

Non-ALE/CALM networks for sending data

Before using an HF Data Modem 3012 to send data to stations not using the ALE/CALM calling system, use the key on the handset to switch scanning off in the NGT, then manually select a channel.

Alternatively, the data modem may be configured to automatically select a channel (see page 5-5, Setting up automatic channel selection).

Table 5-1: Settings for ALE/CALM, Codan Selcall and Voice Only networks operating with an HF Data Modem 3012

Call system Scan setting Call detect time

ALE/CALMa

a. If you use an HF Data Modem 3012 in an ALE/CALM network, scanning is quicker than in other types of networks because the NGT establishes the channel for the data modem.

Set to ‘Scan’ If using the NGT handset, select .

If using NSP, leave the Detect Time field blank.

Codan Selcall or Voice Only

Set to ‘Scan’ If using the NGT handset, select 0.5 seconds.

If using NSP, enter 0.5 seconds in the Detect Time field.

Channel names in the NGT must be numbers in the range 1–9999.



Setting up automatic channel selection

The HF Data Modem 3012 has facilities for controlling the channel selected by the NGT when ALE/CALM is not used.

The channel can be specified by either:

• defining a list of channels to be tried during a call, or

• including the channel to be used in the ATD command

Automatic channel selection allows up to five channels to be programmed into the data modem. The first channel to be tried is the channel on which the last successful call was made. If the call is unsuccessful, the next channel in the list is used.

Channel names in the NGT that are to be used by the data modem must be numbers in the range 1–9999.


��6 Specifications

This chapter lists the specifications of the HF Data Modem 3012. It contains:66

• general specifications (6-2)

• system requirements (6-3)

• environmental specifications (6-3)

• physical specifications (6-3)


Specifications

General specifications

Power requirements

13.5 V DC nominal, 250 mA maximum (operating voltage range 10.5 to 15 V DC)

Data mode

High speed selective repeat ARQ data transfer

2400 bps, 16-channel QPSK (selectable between 4 and 16 channels)

Effective transmission rateuncompressedcompressed

1475 bps (under optimum conditions)Up to 6000 bps

Link establishment mode

Proprietary link establishment 80 baud CHIRP

2400 bps HF modem

TMS320C31 32-bit digital signal processor, 27 MHz

TR.29 based ‘AT’ port, 9600 baud RS232

Data compression

Transceiver control lines and press-to-talk

Front panel indicators

1 × multi-colour LED

Throughput 10 × red LEDs indicating approximately 100 bps per LED when using 16 channels


Specifications

System requirements

Environmental specifications

Physical specifications

HF SSB transceiver (data capable)

Maximum frequency offset error ±100 Hz (between transceivers)

Audio passband 500 to 2500 Hz ±1 dB

Power amplifier ALC—long time constant; peak limiting

Operating environment

Operating temperature 0°C to 55°C

Storage temperature –40°C to +60°C

Relative humidity 100%

Mechanical

Size 210 mm W × 240 mm D × 65 mm H(includes allowance for rear connectors)

Weight 1.9 kg

Sealing IP64

Mounting Free standingFlangeMobile mounting cradle


Specifications



��7 How the data modem works

This chapter provides a general description of how the HF Data Modem 3012 works. It includes:8910

• general description (7-2)

• how the DSP Modem PCB works (7-3)

• how the User Connector PCB works (7-5)


How the data modem works

Technical description

The technical description for the 3012 should be read in conjunction with drawing 03-01080, 3012 HF Data Modem Schematic Block Diagram.

The HF Data Modem 3012 contains two PCBs:

• DSP Modem PCB (Codan part number 08-05860-001)

• User Connector PCB (Codan part number 08-05861-001)

The DSP Modem PCB performs the majority of functions, such as signal processing, and memory and logic functions, while the User Connector PCB performs interfacing, filtering and opto-isolation of the PC serial port.



How the DSP Modem PCB works

The following descriptions should be read in conjunction with drawing 04-03366 sheet 1 and 04-03366 sheet 2 in Chapter 9, Drawings.

The DSP Modem PCB comprises a 32-bit DSP and associated memory, interfacing and power supply components.

Digital signal processor and CoDec

A Texas Instruments TMS320C31 32-bit floating-point DSP (IC101) forms the heart of the data modem. It is interfaced to the transceiver transmit and receive audio paths via a CoDec (IC108), input differential amplifier (stages IC109/A and IC109/B), and audio isolation transformers (T101 and T102).

The CoDec (IC108) is a 14-bit analog to digital/digital to analog converter, which interfaces to the DSP via a serial interface, using frame strobe and clock signals.

A watchdog/power on-reset IC (IC102) ensures that the DSP is held in reset until the power supply rails have stabilised, and also serves to reset the processor if unexpected code run-away stops the strobe line from being regularly toggled.

Memory

The program code for the data modem is stored in two 2 M-bit EPROMs (IC202/204), each organised as 128 k by 16-bit words. These are paralleled to create an effective 128 k of 32-bit memory.

The data modem also requires external SRAM, which is provided by devices IC201 and IC203. Each 128 k by 16-bit device is paralleled to provide a 128 k by 32-bit memory.

A small amount of non-volatile data storage is provided by a 2 k-bit (256 by 8-bit) EEPROM (IC206), which is accessed serially using a 2-wire I2C-compatible serial interface.

Logic and interfacing

A 32-Macrocell programmable logic device (IC106) performs the ‘glue logic’ required to perform several functions, including:

• decoding the memory span of IC101 into the format required by the operating code

• generating read, write and chip-select signals for the memory devices

• inverting the interrupt request signals produced by a dual asynchronous communications element (IC107)

IC107 is a complex device, which features two complete serial communication interfaces with 14 byte FIFOs and an additional parallel port. The primary role of IC107 is to provide the serial interface between the RS232 interface of the data terminal equipment and the DSP.



As the DSP provides very little in terms of useable I/O, IC107 also acts as a peripheral device to provide required I/O functions, including:

• control interfacing to the transceiver (Scan, PTT, Busy and Quiet Line functions)

• serial interfacing for the non-volatile memory (IC205)

• driving the LED indicators via Shift Registers IC206 and IC207

IC107 also connects the digi switch (S101) to the processor. This switch is used to select the operating mode, including special factory test modes.

Throughput

The Throughput indicator on the DSP Modem PCB displays the current data throughput of the data modem. Each LED in the indicator represents approximately 100 bps of data.

Power supply

In order to reduce overall power consumption, a high-efficiency 260 kHz switching regulator generates the main +5 V supply rail.

The switching regulator (IC103) works as a buck converter, together with an inductor (L102), a Schottky diode (D102) and low-ESR tantalum capacitors (C111 and C112) to create the supply. This is further filtered by L103 and C113 to provide a ‘quiet’ analog +5 V supply to feed the CoDec (IC108).

The CoDec (IC108) also requires a negative supply rail, which is generated by a switched-capacitor generator (IC104). The resulting output at pin 5 is regulated at approximately –7 V. However, this rail has far too much ripple to directly feed the CoDec, and so has to be post-regulated by a conventional 3-terminal linear regulator (IC105 (LM79L05)), providing a smooth –5 V DC rail.

If a modulation method other than 16 channels is selected, the throughput indicator shows the capacity of that modulation method.



How the User Connector PCB works

The following descriptions should be read in conjunction with drawing 04-03367 in Chapter 9, Drawings.

Transceiver interface

The data modem and the transceiver are interfaced through connector P1. This interface also provides power to the data modem via a filtering inductor (L1) and a polarity- protection diode (D1). This is a Schottky diode to ensure minimum voltage drop, thereby maximising efficiency and minimising overall current drain.

Power is fed through to the main DSP Modem PCB via connector P2.

The transceiver interface also supports transmit/receive audio, and PTT, SCAN, BUSY and QUIET lines, which allow control between the data modem and the transceiver. Transistor logic is used to interface these signals to IC107 on the DSP Modem PCB. These functions connect to the DSP Modem PCB via connector P3.

Serial ports

The User Connector PCB also performs interfacing of the serial ports.

A conventional charge-pump RS232 driver (IC3) drives the CICS transceiver interface.

IC1, IC4, V14 and V15 combine to provide a more elaborate, fully optically isolated serial interface to a PC or data terminal equipment. Optical isolation on this interface is provided to eliminate possible problems with HF signals entering the PC, or large currents flowing in the grounds of serial cables.

A stand-alone isolated DC−DC converter module (IC1) generates isolated approximate +5 V and +10 V rails. This feeds an RS232 driver (IC4), which uses an internal charge pump to generate a negative rail. Therefore, the TTL level signals from the DSP Modem PCB pass from connector P6, through the opto-couplers and IC4, to the terminal interface via P4.


��8 Maintenance and fault finding

This chapter describes the maintenance and fault finding procedures applicable to the HF Data Modem 3012. It includes:1616

• adjustments and routine maintenance (8-2)

• basic fault finding (8-5)

• advanced fault finding (8-6)


Maintenance and fault finding

Adjustments and routine maintenance

The data modem has been designed so that no routine adjustments or maintenance are required.

A newly commissioned data modem should not require testing as all units have passed a detailed and extensive test procedure at Codan before being despatched.

The data modem is not field serviceable. If a fault is identified, it should be returned to your Codan representative for repair.

PCBs and units available as replacements

The replacement PCBs and units available from Codan are listed in Table 8-1.

Ordering information

Orders for replacement PCBs and units must include the following information. This ensures that the correct parts are supplied and delivery times are kept to a minimum.

• equipment type (e.g. Type 3012 Data Modem)

• PCB (e.g. DSP Modem PCB, 08-0xxxx-001)

• Codan part number (e.g. 08-0xxxx-001)

• serial number(s) of faulty parts and/or units

Table 8-1: Replacement PCBs and units

PCB or unit Part number

DSP Modem PCB 08-05860-001

User Connector PCB 08-05861-001

Final Assembly, data modem

08-05877-001



PCB removal

Safety precautions

Switching off

Ensure that power supplies are switched off before making connections or disconnections between circuit boards.

Handling

Handle circuit boards and touch conductive parts as little as possible.

Grounding

Anything connected to or touching the circuit board tracks should be grounded as follows:

• Ground test equipment connected to a board through its mains lead.

• Discharge static charges, which may build up on a person, by touching a grounded metal surface with both hands. This should be done before working on, and at frequent intervals while working on circuit boards.

• Wear a suitably grounded conductive wrist strap. This minimises the build up of static on you.



Fault finding

If technical assistance is required...

If the fault finding procedures do not locate the fault in the 3012, or if further technical assistance is required for any other reason, please contact your Codan representative. For the most rapid response, please call the Codan office that is currently in office hours (see Table 8-2).

Outside of normal office hours, Codan has Customer Service Engineers on call to provide emergency technical assistance. They will either answer your call immediately or return your call as soon as possible. The contact phone numbers for after hours emergency technical assistance are listed in Table 8-2.

If you are connected to a voice mail system when you call, please follow the instructions carefully, i.e. leave a brief, clear description of your problem and your name and contact phone number including the country code.

Table 8-2: Customer service contact numbers

Region Office hours contact number

After hours contact number

Email address

Asia/Pacific +61 8 8305 0311 +61 8 8305 0427 [email protected]

UK, Europe and Middle East

+44 1252 717 272 +44 1252 741 300 [email protected]

The Americas +1 703 361 2721 +1 703 366 3690 [email protected]



Basic fault finding

To troubleshoot basic faults that may occur with the data modem follow the procedures outlined in the table below.

Table 8-3: Basic fault finding

Condition Action required

All lights on the data modem are off

The data modem is powered via the transceiver. Ensure the cable to the transceiver is firmly secured at both ends and the transceiver is switched on.

Strange characters appear on the screen of the terminal when you type

The data transfer rate (baud) setting for your terminal is incorrect (see page 3-9, Setting up the PC or terminal).

When listening to the transceiver there is a lot of background noise

Check that the data cable between the data modem and the transceiver has the lock nuts tightened at the transceiver end.

Check that the earth cable is secure at the data modem and at the transceiver and that these are appropriately grounded.

A humming noise on the transceiver may be caused by other equipment nearby. Try to identify the source of interference by switching other equipment off. If this is the case, move the transceiver and/or the antenna away from the source of interference.



Advanced fault finding

It is strongly recommended that f

hf data modem · this typeface means... bold/bold a button, switch or connector ... qpsk quadrature...

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