User Guide

Nokia Customer Care System Module
RH-37
Issue 1 07/04 Nokia Corporation Page 23
Figure 6: Internal microphone connection
Internal speaker
The internal earpiece is a dynamic earpiece with an 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
UEMEK and the earpiece driver (EARP & EARN outputs) is a fully differential bridge
amplifier with 6 dB gain.
Figure 7: Speaker connection
IHF speaker
UEMEK has an integrated Audio power amplifier to generate output for the IHF speaker.