External Audio Connector - Nokia RM-362 Service Manual

RM-362; RM-363
System Module
Figure 109 Audio block diagram
UEMcLite supports three microphone inputs and two outputs. The inputs can be used for internal, headset
or handsfree microphones. The microphone signals from different sources are connected to separate inputs
at the UEMcLite ASIC. The inputs and outputs are all differential.
Three inputs (MIC1, MIC2) and two outputs (EAR, HF) are used in the phone.
MIC1P/MIC1N inputs are used for the internal microphone, using single-ended biasing circuitry. EARP/EARN
outputs from UEMcLite are used for hand-portable mode.
Uplink external audio (headset as well as carkit) is connected to MIC2P/MIC2N, while downlink audio is
provided via the HF outputs from UEMcLite. A special situation exists since the carkit can be used with two
different microphones: either the phone's internal microphone (MIC1-inputs) or an external microphone that
connects to the carkit. In these cases UEMcLite is capable of switching between MIC1 and MIC2.
The audio control is taken care of by UEMcLite, which contains the MCU and audio codec. UPP contains DSP
blocks, and handling and processing of the audio signals.
Input and output selection, and gain control is performed inside UEMcLite. DTMF-tones and other audio tones
are generated and encoded by UPP and transmitted to UEMcLite for decoding.

External audio connector

The system connector, containing a 4-pole Jack plug, gains the access to the external audio interface. The
Jack plug, which is integrated in the system connector, contains a mechanical switch, which is used to detect
the connection of the accessories. The configuration for the 4-pole Jack-plug is shown in the following figure.
Figure 110 4-pole jack plug for audio accessory
Issue 1 COMPANY CONFIDENTIAL Page 6 –9
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