External Microphone; Nokia Av Connector - Nokia rx-34 Service Manual

RX-34
System Module
Figure 65 External speakers

External microphone

The signal is not taken from the devices internal microphone but from headset microphone via the Signature
interface.
Microphones used in headsets are electret type and bias voltage (2.1Vdc) for it is taken from the EM ASIC
D1420.
Figure 66 External microphone

Nokia AV connector

A 3.5mm round 4-pole SMD connector is used for stereo audio out, mono audio in (external microphone) and
enhancement identification purposes.
All signals are single-ended type and enhancement identification is implemented throught the same pin that
external mic also uses.
Issue 2 COMPANY CONFIDENTIAL Page 9 –13
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