Epson DFX-8500 service manual Signal Level Parameter Minimum Maximum Condition

DFX-8500
‰￿ Signal Level:		TTL-level compatible, IEEE-1284 level 1 device
		Refer to Table 1-9.
			Table 1-9. Signal Level
	Parameter	Minimum		Maximum	Condition
	VOH*	-		5.5 V
	VOL*	-0.5 V		-
	IOH*	-		0.32 mA	VOH = 2.4 V
	IOL*	-		12 mA	VOL = 0.4 V
	CO	-		50 pF
	VIH	-		2.0 V
	VIL	0.8 V		-
	IIH	-		0.32 mA	VIH = 2.4 V
	IIL	-		12 mA	VIL = 0.8 V
	CI	-		50 pF

Note: * A low logic level on the logical high signal is 2.0 V or less when the printer is powered off. And this signal is equal or exceeding 3. 0 V when the printer is powered on. The receiver shall provide an impedance equivalent to 7.5 K ohms to ground.

‰￿Connector pin assignments and signals: Refer to Table 1-10.

Table 1-10. Signal and Connector Pin Assignment (Forward channel)

Pin No.	Signal Name	Return GND pin	In/Out*	Functional Description
1	/STROBE	19	In	The strobe pulse. Read-in of data is performed
				at the falling edge of this pulse.
2-9	DATA 0-7	20-27	In	The DATA0 through DATA7 signals represent
				data bits 0 to 7, respectively. Each signal is at
				high level when data is logical 1 and low level
				when data is logical 0.
10	/ACKNLG	28	Out	This signal is a negative pulse indicating that
				the printer can again accept data.
11	BUSY	29	Out	A high signal indicates that the printer cannot
				receive data.
12	PE	28	Out	A high signal indicates paper-out error.
13	SLCT	28	Out	Always at high level when the printer is
				powered on.
14	/AFXT	30	In	Not used.
31	/INIT	30	In	The falling edge of a negative pulse or a low
				signal on this line causes the printer to initialize.
				Minimum 50 us pulse is necessary.
32	/ERROR	29	Out	A low signal indicates printer error condition.
36	/SLIN	30	In	Not used.
18	Logic H	-	Out	Pulled up to +5V via 3.9K ohm resistor.
35	+5V	-	Out	Pulled up to +5V via 3.3K ohm resistor.
17	Chassis GND	-	-	Chassis GND.
16,33,19,30	GND	-	-	Signal GND.
15,34	NC	-	-	Not connected.

Note: * In/Out refers to the direction of signal flow from the printer’s point of view.

1-20 Rev. B