User's Manual

2. ELECTRICAL DESCRIPTION

LZT 123 7361 R1A

The power connector electrical characteristics are listed below:

2.2 Audio Connector

A 4-way RJ9 connector, as shown below, allows a telephone handset to

be plugged into the modem, giving access to the microphone and

earpiece signals. The connector may also be used to drive other

analogue audio sub-systems or devices.

Although the GM29 is pre-configured to work with a range of handsets,

the audio interface is flexible and its performance can be configured,

using AT commands, to match a particular handset or audio subsystem.

Pin Signal Dir Limits Description

1 VCC I 5 - 32V Positive power input

2 - - - No connection

3 HR_IN I –0.5 - 32V Active high control line used to switch

off or reset the modem

> 5V, V

< 2V

Power off: 1s < t < 2s

Hard reset: t > 3.5s

4 TO_IN I –0.5 - 32V Active high control line used to switch

on the modem

> 5V, V

< 2V

Power on: t > 0.2s

5 - - - No connection

6 GND I - Negative power (ground) input and

return path for TO_IN and HR_IN

4321

1 MICN

2 BEARN

3 BEARP