Toshiba GD-1221 Manuale Utente
GD-1220/1221
© 2006 - 2008 TOSHIBA TEC CORPORATION All rights reserved
ELECTRICAL CIRCUITS
4 - 10
4.2.5
CI detection circuit
NA/TW models
Fig. 4-10
The CI detection circuit consists of the photocoupler (PC2), ASIC (IC23) on the MAIN board and the
other peripheral devices to detect a ring signal input from the telephone line.
other peripheral devices to detect a ring signal input from the telephone line.
The ASIC makes the CML1 signal become LOW to connect the CI detection circuit to the telephone
line.
When a ring signal is input from the telephone line, the photocoupler is repeatedly turned ON/OFF. This
allows the CI1 signal to become a pulse signal and input to the ASIC on the MAIN board, thereby
detecting the ring signal.
line.
When a ring signal is input from the telephone line, the photocoupler is repeatedly turned ON/OFF. This
allows the CI1 signal to become a pulse signal and input to the ASIC on the MAIN board, thereby
detecting the ring signal.
Signal Name
Type
Active
Description
Destination
CI1
I
-
Line 1 CI Detect Signal
IC23
CN10
Lb
La
0
1
0
1
+12V
RLY2
CML relay
CML1
Q51
3
4
3
3
27
65
17
CI1
17
SG
AG
5VPS
R79
CN9
CN262
PC2
ZD3
ZD1
C1
R2
D52
IC23
ASIC
CN5
CN5
27
65
144
162
NCU board
Line
FAX board
MAIN board
1
12
9
10
4
3
1
2
4
3