Microphone Connector - Motorola GM950E Service Manual

2.0

Microphone Connector

The radio is Þtted with an 8-pin ÔTelcoÕ connector which is connected as follows:
Pin 1.
- No connection.
Pin 2.
- No connection.
Pin 3.
- Microphone (or internal) Hook
This port reads Ô0Õ when the microphone is on-hook and Ô1Õ when the microphone is off-hook. It is
assumed that the hook is a mechanical switch, so the software will always debounce this input.
Pin 4.
- Ground
Pin 5.
- Microphone audio
This microphone signal input is common with the microphone signal input on the accessory connec-
tor and is connected to the microphone path input of the AFIC.
Note: Only one microphone should be connected at any one time.
Pin 6.
- Microphone (or Internal) PTT
The microphone PTT is active low and so this port reads Ô0Õ when the PTT is pressed and Ô1Õ when
the PTT is released. It is assumed that this PTT is a mechanical switch, so the software will always
debounce this input.
The microphone PTT line is also available at the internal connector (J0102:1) as a bi-directional line,
i.e. an internal option can use the line, both to key-up the radio, and to know when the radio is
already keyed-up. For this to work, microprocessor port C4 has to be reconÞgured as an output and
driven low whenever any other signal, other than the microphone PTT, e.g. external PTT, causes the
radio to key-up.
Pin 7.
- BUS+
This line carries the data for the single line serial comms system used in the radio. The RSS will pro-
gram the radio through this socket. The line is also available at the accessory connector Pin 6.
Pin 8.
- Handset Audio
This line provides buffered audio for a handset.
External Device Connectors
Pin Name
1 - -
2 - -
3 Mic. Hook Digital input
4 GND Ground
5 Mic. Audio Analogue input
6 Mic. PTT Digital i/o
7 BUS+ Digital i/o
8 HANDSET Analogue output
Type Connected To
-
-
Port A7
-
AFIC TX IN
Port C4
Port D0 and Port D1
Buffered RX audio
Microphone Connector
B-3