Epson 4500 Interface Specifications

						Interface Specifications
Signal	Return
Pin	Pin	Signal		Direction	Description
13		SLCT		OUT	Pulled up to + 5 volts through 3.3 Kohm
					resistance.
14	-	AUTO		IN	When this signal is LOW, the paper is
		FEED			automatically fed 1 line after printing. (The
		XT			signal level can be fixed to this by setting
					DIP switch 2-4 to on.)
15	-	NC	-		Not used.
16		GND	-		Logic ground level.
17		CHASSIS			Printer’s chassis ground, which is
		GND			isolated from the logic ground.
18	-	NC	-		Not used.
19-30		GND			Twisted-pair return signal ground level.
31	16	INIT		IN	When this level becomes LOW, the printer
					controller is reset to its power-up state
					and the print buffer is cleared. This level is
						normally HIGH; its pulse width must be
						more than 50 microseconds at the
						receiving terminal.
32				OUT		This level becomes LOW when the printer
		ERROR
						is:
						1) in paper out state.
						2) off line.
						3) in error state.
33	-	GND	-			Same as for Pins 19-30.
34	-	NC				Not used.
35				OUT		Pulled up to 5V through 3.3 Kohm
36		SLCT IN		IN		The DC1/DC3 code is valid only when this
						signal is HIGH. (Internal fixing can be
						carried out with Jumper J10. The level of
						this signal is factory-set to LOW.)

Technical Specifications 8-9