EU/AU/AS/C models

NCU board

FAX board

 

 

 

 

 

1

 

8

 

 

 

 

 

 

IC2

 

 

 

 

 

 

 

Line current

 

 

 

 

 

 

 

detection

 

Line

CN3

4

Lb

R26

2

IC

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 4-12

19

20

CN4

CN501

19 REVA1 2

20 REVB1 3

IC29

[IC26]

ASIC

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.

Signal Name

Type

Active

Description

Destination

 

 

 

 

 

REVA1

I

-

Line 1 Current Detection Signal

IC29 [IC26]

 

 

 

 

 

REVB1

I

-

Current Reverse Line 1 Current Detection

IC29 [IC26]

 

 

 

Signal

 

 

 

 

 

 

*Values in [ ] are for GD-1151/1201 in case that the descriptions vary between GD-1150/1200 and GD-1151/1201.

GD-1150/1151/1200/1201/1160/1260

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ELECTRICAL CIRCUITS

 

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Toshiba Model: GD-1150, GD-1260, GD-1160, GD-1201, GD-1151 service manual Line 1 Current Detection Signal IC29 IC26