User Guide

CCS Technical Documentation 7 - Troubleshooting Instructions
RH-26
Issue 1 02/04 ©Nokia Corporation Page 37
Figure 18: System connector series components
Audio
The audio hardware is mostly integrated into the UEMK D200. External amplifier N150 is
needed to drive the internal handsfree speaker (IHF). Other external components are
functioning as capacitors, series resistors and ESD protection components. The required
bias voltages for internal and external microphones are also taken from the UEMK.
Acoustics components are assembled into the phone mechanics. All contacts are spring
type, so in fault situation check that pads on the PWB are clean and spring force is OK.
Earpiece is fed by the differential signals "EARP" and "EARN" from the UEMK. External
earpiece signals is fed by the "HF" & "HFCM" pins.
MIC1N & MIC1P (audio signals) and MICB1 (bias voltage) are used for the internal
microphone. MIC2N & MIC2P and MICB2 are used for external microphone.
IHF circuitry uses XAUDIO(7) output from the UEMK for normal voice. For ringing and
alert tones, which should be heard simultaneously from the headset and IHF speaker, dif-
ferential output (HF&HFCM) from the UEMK is used. The shutdown of the IHF amplifier is
controlled by the UPP using GENIO(13).
Furthermore, a couple of signals are needed to control the external audio device. HEAD-
INT signal is needed for recognising an external device (e.g. headset) connected to the
system. The recognition is based on the ACI-in on the system connector that is sorted to
ground inside the external device used. HOOKINT is generated by a button of an external
device.