User Guide

RH-25
System Module CCS Technical Documentation
Page 16 ©Nokia Corporation Confidential Issue 1 10/2003
Figure 8: Internal microphone connection
Internal Speaker
The internal earpiece is a dynamic earpiece with impedance of 32 ohms. The earpiece is
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 by the
UEM and the earpiece driver (EARP and EARN outputs) is a fully differential bridge
amplifier with 6 dB gain. In RH-25, 8mm leak tolerant PICO earpiece is used.
Figure 9: Speaker connection
IHF Speaker and Stereo Audio Amplifier
Integrated Hands Free Speaker (16mm MALT) is used to generate speech audio, ringing
and warning tones in RH-25. 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.
UEM
MIC1N
MIC1P
EMC
Microphone
Char
ge
Common mode
choke
EARP
EARN
UEM