Read Panasonic KX-HT82480 / KX-HT82470 / KX-HT82460 Service Manual online
13
KX-HT82480/82470/82460 Series
4.2.1.5.
Bell Signal Detection
During on-hook period, transmitting the bell signal to the AC loop in the CR series circuits detects the current by Photo Coupler, and
it determines the presence of a bell signal.
CPU board software performs the operation for recognition and determination of a pattern of bell signals.
it determines the presence of a bell signal.
CPU board software performs the operation for recognition and determination of a pattern of bell signals.
Bell loop path:
1. Ring
R902 PC900 C906 R906 Tip
2. Tip
R906 C906 PC901 R902 Ring
4.2.1.6.
End-Call Signal Detection
End call is detected by the photo coupler at part of making DC loop. PC900 (PC901) 4-pin is High level during a call.
On the other hand, at end-call, PC900(PC901) 4-pin changes from High to Low level.
PC100(PC901) 4-pin (BELLDET/REVDET) is connected to DSP GPIO, and CPU will monitor this signal via DSP and detects end
call.
On the other hand, at end-call, PC900(PC901) 4-pin changes from High to Low level.
PC100(PC901) 4-pin (BELLDET/REVDET) is connected to DSP GPIO, and CPU will monitor this signal via DSP and detects end
call.
+
-
+
-
+
-
REVDET[0]
DP[0]
*RL900A
NC
1
2
3
4
*D904A
NC
2
1
R930A
C926A
IC909A
3
2
1
R944A
D910A
+3.3V_DE56_2
C930A
C935A
C901A
+3.3V_DE56_2
VH1
DG
+3.3V_DE56_2
+3.3V_DE56_2
IC909A
5
6
7
R943A
PC900A
1
23
4
VH1
C904A
C924A
DG
R936A
C921A
C933A
DG
PC903A
1
2
3
4
R920A
C908A
+3.3V_DE56_2
*R901A
+3.3V_DE56_2
R946A
Q900A
C906A
*C905A
*C907A
D908A
3
1
2
4
DG
PC902A
1
3
4
6
*C912A
T900A
3
1
6
4
5
*D902A
*D906A
R981A
VH1
R980A
DG
C960A
*ZNR900A
*C937A
*R908A
*R932A
*C916A
*R938A
*C918A
*R954A
*C928A
*R906A
*R904A
*R948A
*R922A
*R916A
*R934A
*R940A
PC901A
1
2
3
4
*C910A
*Q904A
*R900A
R902A
22
R914A
R918A
R924A
R926A
R928A
680
R950A
R956A
REVDET
BELLDET
BELL DET
REVDET
+
-
+
-
+
-
REVDET[0]
DP[0]
*RL900A
NC
1
2
3
4
*D904A
NC
2
1
R930A
C926A
IC909A
3
2
1
R944A
D910A
+3.3V_DE56_2
C930A
C935A
C901A
+3.3V_DE56_2
VH1
DG
+3.3V_DE56_2
+3.3V_DE56_2
IC909A
5
6
7
R943A
PC900A
1
23
4
VH1
C904A
C924A
DG
R936A
C921A
C933A
DG
PC903A
1
2
3
4
R920A
C908A
+3.3V_DE56_2
*R901A
+3.3V_DE56_2
R946A
Q900A
C906A
*C905A
*C907A
D908A
3
1
2
4
DG
PC902A
1
3
4
6
*C912A
T900A
3
1
6
4
5
*D902A
*D906A
R981A
VH1
R980A
DG
C960A
*ZNR900A
*C937A
*R908A
*R932A
*C916A
*R938A
*C918A
*R954A
*C928A
*R906A
*R904A
*R948A
*R922A
*R916A
*R934A
*R940A
PC901A
1
2
3
4
*C910A
*Q904A
*R900A
R902A
22
R914A
R918A
R924A
R926A
R928A
680
R950A
R956A
REVDET
BELLDET
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