Sony Ericsson GTR-64 manual Audio Conector, Pin Signal Dir Description

GTR64 http://www.matrix.es/GTR64

3.2 Audio Conector

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 GTR-64 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.

1	MICN
2	BEARN
3	BEARP
4	MICP

Audio signal descriptions are listed below:

Pin	Signal	Dir	Description
1	MICN	I	Microphone negative
			input
2	BEARN	O	Earpiece negative
			output
3	BEARP	O	Earpiece positive
			output
4	MICP	I	Microphone positive
			input

MICP and MICN are balanced differential microphone input signals.

These inputs are compatible with an electret microphone. The terminal provides a microphone bias at

2.4V, and can supply at least 1mA of current.

Parameter	Conditions		Min		Typ	Max	Unit
Input voltage full scale	max input gain	14		16		18	mVrms
	min input gain	45		50		56	mVrms
Frequency response	-3dB cut-off	300				3400	Hz
Output dc bias level		2.16		2.4		2.64	V

BEARP and BEARN are the speaker output signals. These are differential-mode outputs.

With a full-scale PCM input to the CODEC, 0 dB audio output gain setting, and a differential load RL = 30Ω, the output voltage between EARP and EARN is 1.5 V rms.

For load resistances less than 30Ω, the full-scale output needs is limited using the modules internal programmable gain attenuator.

GTR64 Integrators Manual V.1.2 Pag. 14 Preliminary. Subject to change without prior notice