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GD-1150/1151/1200/1201/1160/1260 © 2003 - 2008 TOSHIBA TEC CORPORATION All rights reserved
ELECTRICAL CIRCUITS
4 - 12
EU/AU/AS/C models
Fig. 4-12
The line current detection circuit consists of the line current detection IC (IC2), ASIC (IC29 [IC26]) on
the FAX board, and the other peripheral devices. It detects a dial tone and the hook status of the exter-
nal telephone from the current flowing through the line.
When a dial tone is input from the telephone line, current flows through the line. The line current detec-
tion IC sends REVA1 and REVB1 to the ASIC as pulse signals. This allows a dial tone to be detected.
* Values in [ ] are for GD-1151/1201 in case that the descriptions vary between GD-1150/1200 and
GD-1151/1201.
Signal Name Type Active Description Destination
REVA1 I - Line 1 Current Detection Signal IC29 [IC26]
REVB1 I - Current Reverse Line 1 Current Detection
Signal
IC29 [IC26]
CN3
Lb
R26
Line
REVA1
REVB1
19
4
20
1
2
8
7
19
20
2
3
NCU board FAX board
IC29
[
IC26
]
ASIC
CN4
CN501
IC2
Line current
detection
IC
08/03