Toshiba GD-1160, GD-1260, GD-1250, GD-1270 Line path switching control circuit, CML1, ATT3DB1

4.2.2Line path switching control circuit

NA/TW models

		NCU board		R4
			C5
						Q51								3
			+12V	RLY2
			CML relay											6
			1		12	AG			R67
				1	8	T1				R71
		4 Lb	9
				0	10
Line	CN10									IC51	9,11			CN9
				1							10
		3 La	4
				0	3					Analog
										switch		IC53
						AG			3 1
											4	1	2	1
										0
						IC53
						5	7	R59	1	1		IC52
		3 a2									15	6	7	2
									2	0
						6
	CN11
External							R66		13	1
telephone		4 b2								0	14
							R68
						Ring signal
						detection
						circuit
								Fig. 4-5

FAX board

3 CML1 21

6 ATT3DB1 22

CN501

1TXOUT1 28,29

2RXIN1 32

IC29

[IC26]

ASIC

IC12 [IC9]

MODEM

4

The line path switching control circuit consists of the CML relay (RLY2) and analog switch (IC51) on the NCU board, the ASIC (IC29 [IC26]) on the FAX board and the other peripheral devices.

The CML relay is switched according to the CML1 signal output from the ASIC on the FAX board. When the CML1 signal goes HIGH, Q51 comes on to turn ON the CML relay.

The analog switch is switched according to the CML1 signal and ATT3DB1 signal. When the CML1 sig- nal or ATT3DB1 signal goes HIGH, the analog switch is turned ON.

Turning ON the CML relay and analog switch allow the MODEM to be connected to the line.

Signal Name	Type	Active		Description	Destination
CML1	O	H	Line 1	CML Relay Control Signal	RLY2, IC51
ATT3DB1	O	H	Line 1	Attenuator Control Signal	IC51

*Values in [ ] are for GD-1250/1270 in case that the descriptions vary between GD-1210 and GD- 1250/1270.

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	ELECTRICAL CIRCUITS

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08/04