Accessory Connector Pin Functions
1-14
Radio Installation
7.1
GM1200E Databox Radio Connections
NPD Call Request - Logic input to radio from terminal equipment. Activation of line where call
destination is valid NPD address.
Clear to Send - Logic output from radio to terminal equipment indicates that the radio is operational
on an allocated data traffic channel.
Send/Receive - Direction of NPD data, (PTT on for send, PTT off for receive).
Tx Audio - Analogue input modulating signal to radio from terminal equipment. Used to frequency
modulate the radio. Input should be common with external accessory connector (pin 2).
Rx Audio - Analogue output signal from radio to terminal equipment, which is the demodulated
signal of the received RF.
Clear - Logic input to radio from terminal equipment. Activation of line will immediately clear the call.
Note:
Application notes dealing with the functionality of NPD are given in Appendix C of the Basic
Service Manual.
7.2
Radio Power Up/Down
Power to the radio is via the supply line and the radio is normally switched on/off using the On/Off
button, however for a data radio this is not feasible.
The following outlines the GM1200E Databox power up/down logic, and provides recommendations
for installation.
A Non Prescribed Data (NPD) call set up via the radio accessory connector EMERGENCY LINE
(pin 9) will power up the radio, however the radio will remain powered up until the supply line
voltage is removed.
Table 1-1 Non-Prescribed Data (NPD Pin Functions)
External (Accessory Connector)
Pin
Function
9
Call 1 (NPD Call Request)
12
Clear To Send (CTS)
3
Send/Receive
5
Tx Audio (NPD Data Out)
11
Rx Audio (NPD Data In)
14
Clear
10
Ignition Sense
7
Ground
