Toshiba GD-1250, GD-1260, GD-1270, GD-1160 Description of Circuits, Configuration, NA/TW models

4.2Description of Circuits

4.2.1Configuration

This section describes the function of each circuit.

The NCU board consists of the transformer, relay, analog switch and other peripheral devices. It con- trols switching of the line path, generates the dial pulses, detects the line current and ring signal, and monitors the line.

The NCU board is connected to CN501 on the FAX board. It can be also connected optionally to CN502.

The description in this section is based on the NCU board for Line 1.

NA/TW models

		NCU board
								REVA
								REVB
			Line current			IC53
		Lb		T1				TXOUT
			detection
	CN10
Line			circuit
		La			IC51
				IC53	Analog	IC52
				AG				RXIN
					switch
				~
				DB1		IC52
							CNG signal
			-	+				ANSDET
							detection
							circuit
				~
				Dial pulse				LD
				generation
								CN9
		a2		circuit					FAX board
External	CN11			DC
telephone		b2		consumption				ATT3DB
				circuit
								CML
				1
				0
				1
				0
				RLY2
				CML relay
				Ring signal				CI
				detection
				circuit
				Fig. 4-3

4

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	ELECTRICAL CIRCUITS

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