User's Manual
2. ELECTRICAL DESCRIPTION
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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
V
IH
> 5V, V
IL
< 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
V
IH
> 5V, V
IL
< 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
4 MICP