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13
KX-TGJ310/KX-TGJ312/KX-TGJ320/KX-TGJ322/KX-TGJA30
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
→ C105 → R103→ C110→ R111→ C111→Pin12 of IC501 [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 turns off. Q141 is disconnected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an
on-hook condition.
on-hook condition.
Pulse Dial Circuit:
Pin 13 of BBIC(IC501) 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.
L1T
L1R
C110
820p
C109
820p
C113
0.082u
+1.8V
3
7
1
C
u
1
.
0
4
4
1
Q
*
3
D
N
G
Q161
B
C
E
C142
K0.01u
*Q141
B
E
C
C152
0.01u
L2R
L2T
*C143
N
C
R11
7
100
k
C116
100n
R116
5.6M
R115
5.6M
C115
100n
R118
100
k
D132
NC
D133
NC
*C16
7
2
7
00p
*C164
0
.1u
*C162
10u
*C166
NC
P101
*S
A101
2
1
D101
1
4
2
C101
680p
C102
680p
C106
680p
C105
680p
R163
39
*C120
N
C
*C121
N
C
*R120
NC
GAP
1
2
R16
7
NC
*S
A102
NC
2
1
*D143
NC
*C1
7
1
0.039u
*D142
NC
*C161
N
C
C111
0.033u
C103
0.01u
C104
0.01u
*D141
Q142
C184
1u
R102
5.6M
R101
5.6M
R103
180k
R104
180k
R109
82k
R11
08
2
k
R111
3.9k
R11
2
120
k
*R11
9
NC
R141
100k
R142
2.
7k
*R146
1
0
*R144
1
0
k
R145
3.9
k
*R148
680
R151
100k
*R160
270
*R16
2N
C
*R169
3
9
k
4
6
1
R
*
k
2
.
2
R165
2
7k
R166
8.2
k
R168
4.
7k
*R1
7
0
1.5
k
*R14
7
10
K
*C141
R152
130
k
*Q143
NC
R143
NC
*R153
NC
*R154
NC
C181
560p
GND3
(YELLOW)
RX
TX
(BROWN)
(RED)
(BLACK)
NL_CID
3
Pin 26 of IC501
Pin 25 of IC501
Pin 1
1
o
f IC501
Pin 14 o
f IC501
Pin 13 o
f IC501
P
A
RA
DET
PUL
S
E MUTE
HOOK
CALLER ID/BELL
DETECTION
Pin 18 of IC501
Pin 17 of IC501
Pin 17 of IC501
Pin 12 of IC501
Pin 19 o
f IC501
Pin 21 o
f IC501
Pin 22 of IC501
Pin 15 of IC501
4.
7
u
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