GM 300 8- and 16-Channel Radio Accessory Connector
Kit #HLN9457

The following is a description of the pin functions on the Expanded Accessory Connector for the 8- and 16-channel GM 300 radios. Refer to Figure 1. for pin locations in the connector housing.

1.    External Speaker Negative
2.    Microphone Audio 80 mV RMS @ 60% Deviation3.    Microphone PTT
4.    External Alarm (not supported)
5.    Flat Transmit Audio 150 mV RMS @ 60% Deviation
6.    Not Used
7.    Ground
8.    COR Output-Receiver Unsqelched Indicator (Active Low)
9.    Emergency Alert Input (not supported)
10.    Ignition Control Input
11.    Discriminator Audio Output 600 mV RMS @ 60% Deviation
12.    Not Used
13.    Switch A + Sense 0.5 Amps Max.
14.    Remote Hook Switch Input
15.    Internal Speaker Positive
16.    External Speaker Positive 

Note: The above pin-outs are also applicable to the following model(s): M120

GM 300 16-Channel Radios

1.    External Speaker Negative
2.    Microphone Audio 80 mV RMS @ 60% Deviation
3.    Microphone PTT
4.    Programmable Output -- See table on next page
5.    Flat Transmit Audio 150 mV RMS @ 60% Deviation
6.    Programmable Input -- See table on next page
7.    Ground
8.    Programmable Input/Output -- See table on next page
9.    Programmable Input -- See table on next page (Defaults to Emergency Alert Input)
10.    Ignition Control Input
11.    Discriminator Audio Output 600 mV RMS @ 60% Deviation
12.    Programmable Input/Output -- See table on next page
13.    Switch A + Sense 0.5 Amps Max.
14.    Programmable Input/Output -- See table on next page
15.    Internal Speaker Positive
16.    External Speaker Positive

.

Figure 1. Accessory Connector, Rear View

Figure 2. Extracting a Terminal