SIEMENS A75
Manual de Servicio

Company Confidential
Copyright 2005© Siemens AG

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8 Acoustic
The speaker module is designed to provide good performance for mobile handsfree and

sound ringer. The speaker module is a system which has a closed front volume with soundoutlets towards the ear of the user. The speaker is partly hidden behind the display to save length of the phone. The back volume of speaker module is using the unused air between the antenna and the PCB. The speaker module is connected to the SAR-frame and contacted via two bending springs to the PCB. For avoiding any interference between antenna and earpiece, there is an antenna reference plate soldered behind the speaker at the PCB. In ringer mode acoustic shock is avoided by using ramping of the ringer level. The microphone is built in the Mounting Frame Lower Part and is mechanically fixed with a rubber seal (gasket). The contact on the PCB is realised via spiral springs, which are integrated in the gasket. Because of usage of Unidirectional Microphone, the gasket has a front- and a back sound-inlet hole. The front sound-inlet is acoustically tighten connected with a sound-inlet at the rear-side of the mounting frame lower part. The back sound-inlet is acoustically tighten connected with a sound-inlet at the bottom-side of the mounting frame lower part. The gasket of the microphone has a asymmetrical shape in order to provide nonrotating, guaranteed covering of the sound-inlets of mounting frame lower part to the corresponding sound-inlets at microphone gasket. The buzzer and the keypad clicks will be realized over the earpiece. The standard sounds will be generated by the EGOLDlite, the advanced sounds will be generated via firmware running on the DSP.

9 Power Supply, Battery and Charging
All the important functions for the power supply of the phone are carried out by the power supply ASIC. The POWER-pin of the I/O-Connector is for charging the battery with an external power supply.

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