Epson 500 manual 137

Pin assignments

Signal	Return
Pin	Pin	Signal				Direction	Description
1	19					IN		pulse to read data.
				STROBE			STROBE
2	20			DATA 0		IN	These signals represent
3	21			DATA 1		IN	information in bits 0 to 7 of
4	22			DATA 2		IN	parallel data respectively.
5	23			DATA 3		IN	Each signal is at HIGH level
6	24			DATA 4		IN	when data is logical 1 and
7	25			DATA 5		IN	LOW when it is logical 0.
8	26			DATA 6		IN
9	27			DATA 7		IN
10	28					OUT	About a 5-μs pulse. LOW
			ACKNLG
							indicates data has been
							received and the printer is
							ready to accept more data.
11	29				BUSY	OUT	A HIGH signal indicates the
							printer cannot receive data.
							The signal goes HIGH in the
							following cases:
							1) During data entry
							(for each character)
							2) During initialization
							3) During self test,
							demonstration, and
							default-setting printing
							4) During a printer-error state
12	28				PE	OUT	A HIGH signal indicates the
							printer is in a paper-out state
							or in an error state
13	28				SLCT	OUT	Always at high when printer is
							on
14	30					IN	Not used
					AUTO
					FEED
					XT
15	—				NC	—	Not connected
16	—				GND	—	Logic ground level
17	—		CHASSIS			—	Printer’s chassis ground,
					GND		which is connected to the
							logic ground

A-10Technical Specifications