Panasonic DP-2500, Technical Manual

Page: 23 / 342

23
1.1.13. Line Control Board
The following shows a block diagram of the Line Control Board.
The Ring Detector consists of a photocoupler, PC2 (PC1 for LCE), and its peripheral circuits. The ringing
signal is a half-wave rectifier in the Ring Detector, and transferred through the nCTON signal line to the
IC80 on the SC PC Board. The IC80 observes the signal to distinguish from signals caused by chattering.
The Off-Hook Detector (External Telephone) circuit consists of the photocoupler, PC1 (PC2 for LCE), and
its peripheral circuits. When PC1 detects loop current flow, it emits a Low active output signal (nHKOF) to
the IC80 which monitors it for a specified time. If the IC80 detects no change in the Low signal level, it deter-
mines that the External Telephone is Off-Hook.
MODEM
ApI
PC2
PC1
CML
PLS
TCK
Ringing
Detector
Line
Telephone
CML
PC1
nCTON
RMCK
RMCS
RMDT
CLK
P/S
Q8
PC2
JP18~23
Country
Code
Jumper
IC2
CML
PLS
TCK
+24V
+24V
+24V
Q1
Q3
Q4
Off-Hook
Detector
HYBSR
<MDM> < LCE >
L : Ring In
H : FAX Side
H : Make
CN8 CN25
11 11
10 10
7 7
8 8
9 9
5 5
6 6
CMLD
PLSD
14 14
Ringer
Off-Hook
Dial Pulse
Loop Relay TCKD
[DZYNA1436*]
MODEM
PC2
CML
PLS
Ring
Detector
Line
Telephone
CML
C5
Q2
Off-Hook
Detector
HYBSR
< MDM > < LCU >
PC1
GND
T2
Q1
PC1
nCTON
PLS
CML
+24V
CMLD 5
PLSD 6
PC2
nHKOFF 9
+5V
+5V
L : Off-Hook
H : On-Hook
L : Ring In 10
H : FAX Side
CN7
H : Make
for Auto Receive
API
[DZYNA1435*]
MODEM
PC1
PC2 CML
PLS
Ring
Detector
Line
Telephone
CML
C5
Q2
HYBSR
< MDM > < LCE >
GND
T2
Q1
PC2
nCTON
PLS
CML
+24V
CMLD 5
PLSD 6
PC1
nHKOFF 9
+5V
+5V
L : Off-Hook
L : Ring In 10
H : FAX Side
CN7
L : Break
API
[DZEP000441]
L : Telephone
L : Break
L : Telephone
L : Break
H : On-Hook
L : Telephone
H : Make