User Guide

Nokia Customer Care System Module

Company Confidential RH-30/RH-31

Internal audio

IHF speaker & stereo audio amplifier

Integrated Hands Free Speaker, 16mm MALT, is used to generate speech audio, alerting

and warning tones in RH-30/RH-31. Audio amplifier is controlled by the UPP. Speaker

capsule is mounted in the C-cover. Spring contacts are used to connect the IHF Speaker

contacts to the main PWB.

Figure 12: IHF speaker and amplifier

Internal microphone

The internal microphone capsule is mounted to in the UI-frame. Microphone is omni

directional and it’s connected to the UEM microphone input MIC1P/N. The microphone

input is asymmetric and the UEM (MICB1) provides bias voltage. The microphone input

on the UEM is ESD protected. Spring contacts are used to connect the microphone to the

main PWB.

Figure 13: Internal microphone

Internal speaker

The internal earpiece is a dynamic earpiece with impedance of 32 ohms. The earpiece

must be low impedance one since the sound pressure is to be generated using current

and not voltage as the supply voltage is restricted to 2.7V. The earpiece is driven directly