KX-TU301RUME - Panasonic Telephone Service Manual (repair manual). Page 8

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8
KX-TU301RUME
4.2.
Circuit Operation (Handset)
4.2.1.
Outline
Handset consists of the following ICs as shown in Block Diagram (Handset) (P.7).
• GSM Module : MOD1
- GSM (GSM900/DCS1800) Network interface
- GSM Audio
Half Rate, Full Rate, Enhanced Full Rate (HR/FR/EFR), 
Adaptive Multi-rate (AMR), Echo cancellation, Noise reduction
- SIM card interface
4.2.2.
Power Supply Circuit
The power is supplied to the GSM module, Audio circuit, LCD, SIM card from Battery(+3.8v)as shown in Fig.101.The power
supply is as follows.
BAT+(3.8V) 
→ MOD1 → Audio circuit
BAT+(3.8V) 
→ MOD1 → LCD
BAT+(3.8V) 
→ MOD1 → SIM card
BAT+(3.8V) 
→ LED Power IC → LED
BAT+(3.8V) 
→ LDO → Vibrator
Fig.101
3.8V
VANA 2.5V
BAT+
GSM
 Audio circuit
module
BAT-
 MOD1
VIO 2.85V
   LCD
VSIM 2.85/1.80V
  SIM card
LED Power IC
IC3
LED
LDO
IC4
Vibrator
BAT
On
Off
VIO
2.85 V
Reset 
(RETn)
1
2
3
S
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