Figure 109 Audio block diagramUEMcLite supports three microphone inputs and two outputs. The inputs can be used for internal, headsetor handsfree microphones. The microphone signals from different sources are connected to separate inputsat 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/EARNoutputs from UEMcLite are used for hand-portable mode.Uplink external audio (headset as well as carkit) is connected to MIC2P/MIC2N, while downlink audio isprovided via the HF outputs from UEMcLite. A special situation exists since the carkit can be used with twodifferent microphones: either the phone's internal microphone (MIC1-inputs) or an external microphone thatconnects 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 DSPblocks, and handling and processing of the audio signals.Input and output selection, and gain control is performed inside UEMcLite. DTMF-tones and other audio tonesare generated and encoded by UPP and transmitted to UEMcLite for decoding.External audio connectorThe system connector, containing a 4-pole Jack plug, gains the access to the external audio interface. TheJack plug, which is integrated in the system connector, contains a mechanical switch, which is used to detectthe connection of the accessories. The configuration for the 4-pole Jack-plug is shown in the following figure.RM-298; RM-299System ModuleIssue 1 COMPANY CONFIDENTIAL Page 6 –9Copyright © 2007 Nokia. All rights reserved.
