Toshiba GD-1160, GD-1260, GD-1250, GD-1270, GD-1210 service manual EU/AU/AS/C models, FAX board

EU/AU/AS/C models

NCU board FAX board

					1		8
						IC2
						Line current
						detection
Line	CN3	4	Lb	R26	2	IC	7

Fig. 4-10

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-1250/1270 in case that the descriptions vary between GD-1210 and GD- 1250/1270.

GD-1210/1250/1270/1160/1260	© 2006 - 2011 TOSHIBA TEC CORPORATION All rights reserved
ELECTRICAL CIRCUITS

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