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RH-20
Company confidential
System Module and User Interface
CCS Technical Documentation
Page 54
  Nokia Corporation.
Issue 1  10/2003
Internal microphone
The internal microphone capsule is mounted in the UI-frame. Microphone is omnidirec-
tional and it is connected to UEM microphone input MIC1P/N. The microphone input is 
asymmetric and the UEM (MICB1) provides the bias voltage. Nominal impedance of the 
microphone is 1.8kOhms. The microphone input to UEM is ESD protected. Spring con-
tacts are used to connect the microphone to the main PWB. Microphone is mounted in 
LCD frame assembly.
IR module
The IR interface in case of transceiver with 1.8V I/O voltage is designed into UPP. The IR 
link supports transmission speeds from 9600 bit/s to 1.152 MBit/s up to distance of 80 
cm. Transmission over the IR if half-duplex.
The length of the transmitted IR pulse depends on the speed of the transmission. When 
230.4 kbit/s or less is used as a transmission speed, pulse length is maximum 1.63
µs. If 
transmission speed is set to 1.152Mbit/s, the pulse length is 154ns.
Figure 28: IR module connections.
Vibra
A vibra alerting device is used to generate a vibration signal for an incoming call. Vibra is 
located in the bottom end of the phone and it is connected to main PWB with spring 
contacts. The vibra is controlled by a PWM signal from UEM. Frequency can be set to 64, 
128, 256 or 512 Hz and duty cycle can vary between 3% - 97%. Vibra motor is mounted 
in C-cover assembly.
IR_TX 
IR_RX 
SD 
UPP 
VFLASH1 
VBAT
VIO 
IR-
UEM