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14
KX-TGF310RUM/KX-TGF320RUM/KX-TGF320UCM/KX-TGFA30RUM
4.5.5.
Telephone Line Interface
<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 (RINGING) 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:
L1T
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
L1T
C105 R103 R110 R111 R112 BBIC pin18 (RINGING)
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 19 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.
OFF Hook
BELL signal detection
C174
C171
R166
R178
RX
Pin25 of IC501
Pin25 of IC501
TX
Pin27 of IC501
Pin27 of IC501
R160
+
C161
C167
R165
R162
C173
R151
R164
C184
C103
C111
Q161
E
B
C
R163
R1
17
C1
15
R109
C109
Q141
Q142
C101
P101
L1T
L1R
D101
C102
1
2
3
+
~~
_
4
R145
C142
C152
R152
A
K
D142
R141
B
E
C
E
B
C
R142
SA101
R111
R101
HOOK
Pin19 of IC501
Pin19 of IC501
CIDOUT
Pin24 of IC501
Pin24 of IC501
LSRn
Pin28 of IC501
Pin28 of IC501
RINGING
Pin18 of IC501
Pin18 of IC501
CIDINn
Pin23 of IC501
Pin23 of IC501
CIDINp
Pin21 of IC501
Pin21 of IC501
R168
PARADET
Pin17 of IC501
Pin17 of IC501
ADC1
Pin33 of IC501
Pin33 of IC501
ADC0
Pin32 of IC501
Pin32 of IC501
R1
18
C1
16
R115
R116
R1
10
C1
10
R112
C113
C105
R103
C104
R102
C106
R104
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