Read Panasonic KX-UT248RU / KX-UT248RU-B (serv.man3) Service Manual online
9
KX-UT248RU/KX-UT248RU-B
4.2.4.
Analog Circuit
1. Speaker phone call
Transmitting signal is input from microphone
→ input to IC103-pin 83,84 → A/D conversion, Gain adjustment and echo cancel
by a built-in DSP of IC103
→ D/A conversion → output IC103 pin 98,99 → input to IC503-pin A16,B16 → A/D conversion,
Gain adjustment
→ IP Line.
Receiving signal input from IP Line
→ Gain adjustment and D/A conversion by DSP of IC503 → output from IC503-pin
A13,B13
→ input to IC103-pin 93,94 → A/D conversion, Gain adjustment → D/A conversion → output IC103 pin 78,79 →
Amplified by IC101 and output to Speaker.
Class D Amp IC101 is controlled as follows;
IC101-pin1 H (3.3V): Amp ON , IC101-pin1 L (0V): Amp OFF
Class D Amp IC101 is controlled as follows;
IC101-pin1 H (3.3V): Amp ON , IC101-pin1 L (0V): Amp OFF
2. Handset call
Transmitting signal is input from handset microphone
→ input to IC503-pin A14,B14 → A/D conversion, Gain adjustment by a
built-in DSP of IC503
→ IP Line.
Receiving signal input from IP Line
→ Gain adjustment and D/A conversion by DSP of IC503 → output from IC503-pin C13 →
output to handset speaker.
C1004
C1003
C1005
DG
L101
C106
C109
DG
DG
DG
C115
C105
C131
C128
C129
DL101
1
2
3
C113
C118
C130
C108
L102
C176
IC101
1
STBY
2
NC
3
IN+
4
IN-
5
OUT+
6
VDD
7
GND
8
OUT-
9
FIN
D104
SPN
SPP
SP
5V
D103
DG
SN
C152
C153
DG
R104
R106
DG
R121
C136
R123
R128
C110
R120
R107
D102
R129
D101
R140
R134
C149
R145
C167
C156
C162
C164
C124
C125
MICN
MICP
MIP
MIN
C172
C174
R108
3.3VA
AG
AG
AG
AG
AG
AG
AG
AG
R122
R116
C103
DG
C134
C142
IC103
84
98
99
93
94
83
78
79
C143
DG
C144
DG
R550
C122
C121
IC503
C119
C120
B16
A16
A13
B13
P4
BBIC
HSMICINP
IC503
BBIC
C140
R130
R131
R132
C177
R125
C139
C138
JK101
1
2
3
4
5
C137
C193
C135
D106
C192
R133
D107
C191
R126
L107
C141
D105
R160
R161
C155
C154
3.3VA
AG
C157
C158
AG
AG
AG
AG
AG
AG
AG
AG
C527
AG
R115
C159
AG
R127
R101
C102
A14
C13
B14
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