Wavecom WMOi3 Bedienungsanleitung PDF herunterladen (Seite 12)

WMOi3 Integrated modem 25/01/00

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3.2.4. AUDIO

The modem allows the connection of a handset or a headset through

AUDIO signals

The audio end stage must respects the following specifications :



Microphone

The microphone inputs are differential inputs. They already

contain the necessary biasing for an electret microphone

(0,5 mA and 2 Volts). Connection is direct. The impedance

of the microphone has to be around 2k

Ω

. The microphone

inputs gain can be adjusted by AT command. Gain can be

tuned from 30dB to 51dB. Connection can be differential or

single-ended but it is recommended to use differential

connection to reject common mode noise and TDMA noise.



Speaker

Speaker outputs are push-pull amplifiers and can drive loads

down to 50 Ohms and up to 1nF. These outputs are

differential and the output power can be adjusted by step of

2dB with AT command. The output can be connected

directly to a speaker. Connection can be differential or

single-ended but it is recommended to use differential

connection to reject common mode noise and TDMA noise.

The audio signal are :

Signal Pin number Description

MIC1P 20 Microphone 1 positive input

Audio 1 MIC1N 22 Microphone 1 negative input

SPK1P 12 Speaker 1 positive output

SPK1N 14 Speaker 1 negative output

MIC2P 16 Microphone 2 positive input

Audio 2 MIC2N 18 Microphone 2 negative input

SPK2P 10 Speaker 2 positive output

SPK2N 8 Speaker 2 negative output

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Wavecom WMOi3 Bedienungsanleitung Seite 12