User Guide

Figure 105 Internal microphone circuitry
External microphone
Galvanic accessories are connected to the system connector (Pop-Port
TM
).
Accessory audio mode is automatically enabled/disabled during connection/disconnection of dedicated phone
accessories.
External microphone circuitry is biased by Retu ASIC MicB2 bias voltage output. The circuitry provides a
symmetrical connection for the microphone from the Pop-Port
TM
connections, XMICN and XMICP, to Retu ASIC
inputs, Mic2P and Mic2N.
Figure 106 External microphone circuitry (Pop-Port connects to the right side)
Internal earpiece
Internal earpiece is used for the HandPortable (HP) call mode. A dynamic 8mm earpiece capsule is connected
to Retu ASIC’s differential output EarP and EarN.
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