Read Panasonic KX-TGK310RUB / KX-TGK320RUB / KX-TGKA31RUB Service Manual online
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KX-TGK310SP/KX-TGK310JT/KX-TGK320JT/KX-TGK310FR/KX-TGK310RU/KX-TGK320RU/KX-TGK310NE//KX-TGK310GR/KX-TGKA31EX/KX-TGKA31RU
4.3.5.
Telephone Line Interface
Telephone Line Interface Circuit:
Function
Function
• Bell signal detection
• ON/OFF hook and pulse dial circuit
• Side tone circuit
• ON/OFF hook and pulse dial circuit
• Side tone circuit
Bell signal detection and OFF HOOK circuit:
In the idle mode, Q141 is open to cut the DC loop current and decrease the ring load. When ring voltage appears at the Tip (T)
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T
R111 C110 Q111 BBIC pin 5 [BELL]
When the CPU (BBIC) detects a ring signal, Q141 turns on, thus providing an off-hook condition (active DC current flow through
the circuit). Following signal flow is the DC current flow.
T
the circuit). Following signal flow is the DC current flow.
T
D101 Q141 Q161 R163 D101 P101 R
ON HOOK Circuit:
Q141 is open, Q141 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an on-
hook condition.
hook condition.
Pulse Dial Circuit:
Pin 6 of BBIC turns Q141 ON/OFF to make the pulse dialing.
Side Tone Circuit:
Basically this circuit prevents the TX signal from feeding back to RX signal. As for this unit, TX signal feed back from Q161 is
canceled by the canceller circuit of BBIC.
canceled by the canceller circuit of BBIC.
PULSE_MUTE
BELL
HOOK
NL_CID
R121
390k
R122
390k
C120
1000p
+3.0V
+3.0V
C331
NC
VDDC
L2R
L1R
L1T
L2T
*R123
NC
*R124
10
*Q140
B1ABCE000009
R141
100k
R142
2.7k
*R144
NC
C143
NC
C142
0.01u
Q161
C152
0.01u
*C164
0.1u
C181
NC
R117
100k
R115
5.6M
R116
5.6M
R118
100k
C115
100n
C116
100n
*Q141
Q111
D133
D132
D113
C161
10u
*C166
NC
C178
0.1u
Q171
*C141
N
C
R114
68k
*R14
8
10k
*R149
680
*R16
2
NC
R165
27k
C113
0.01u
0
7
2
0
6
1
R
*
*R159
1.5
k
4
6
1
R
*
k
2
.
2
k
1
7
7
1
R
R113
22k
R111
1M
R112
47k
*C167 2700p
R158 4.7k
RA151
1k
1
2
3
4
C101 680p
C102
680p
C121 680p
C122 680p
C122 680p
D101
1
4
3
2
R176
1k
C103
NC
*C104
NC
*R103
1.2k
R163
39(0.5W)
GAP
1
2
C110
0.1u
C112
0.1u
R171
220
R172
680k
R175
3.9k
*R104
NC
R167
NC
C173
0.027u
C175
560p
*D142
SA102
NC
2
1
*SA101
2
1
P101
C176
1u
R151
100k
R152
130k
D143
NC
L101
27n
C476
NC
*C475
10pF
2
4
1
Q
4
8
1
C
u
1
C507
2.2u
*D141
R131
NC
R133
NC
C132
NC
*R154
NC
*R153
NC
*Q144
NC
*C479
10pF
*R16
9
39k
*R145
2.2k
*C171
0.033u
DC Monitor
Caller ID
Bell detection
P
in 28 of IC501
P
in 25 of IC501
P
in 24 of IC501
P
in 16 of IC501
P
in 18 of IC501
P
in 19 of IC501
P
in 17 of IC501
Pin 6 of IC501
Pin 5 of IC501
HOOK
BELL
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