Epson LX-90TM OUT, D-5, Signal, Notes:, “Return” denotes the

Table D-3, continued
Signal	Return		Signal			Direc-			Description
Pin	Pin					tion
1 3	-	SLCT			OUT			Pulled up to + 5 volts through 3.3K
								ohm resistance.
								Unused.
14	-		NC	-
1 5	-		NC	-				Unused.
1 6	-		N C	-				Unused.
1 7	-	C H A S S I S						Printer’s chassis ground, which is
			G N D	-				isolated from the logic ground.
18	-		NC	-				Unused.
19 - 30	-		GND	-			Twisted-pair return signal ground level.
						IN		When this level becomes LOW, the
3 1	-		INIT
								printer controller is reset to its power-
								up state and the print buffer is
								cleared. This level is usually HIGH; its
								pulse width must be more than 50
								microseconds at the receiving
								terminal.
3 2						OUT		This level becomes LOW when the
	-		ERROR
								printer is in:
								1) Paper-end state.
								2) Off-line.
								3) Error state.
33	-		NC	-				Unused.
34	-		NC	-				Unused.
3 5	-		NC	-				Unused
3 6	-		NC	-				Unused.

Notes:

1.The column heading “Direction” refers to the direction of signal flow as viewed from the printer.

2.“Return” denotes the twisted-pair return, to be connected at signal ground level. For the interface wiring, be sure to use a twisted-pair cable for each signal and to complete the connection on the return side. To prevent noise, these cables should be shielded and con- nected to the chassis of the host computer or the printer but not at both ends.

3.All interface conditions are based on TTL level. Both the rise and the fall times of each signal must be less than 0.2 microseconds.

D-5