Epson SQ-2550, SQ-850 Interface Specifications, Parallel interface, 8-10Technical Specifications, Your printer is equipped with both a parallel and a serial interface

Interface SpecificationsParallel interfaceYour printer is equipped with both a parallel and a serial interface.

Connector pin assignments and a description of their respective interface signals are shown in the following table.

Signal		Return	Signal	Direction			Description
Pin		Pin
1					IN		pulse to read data. Pulse
	19		STROBE			STROBE
						width must be more than 0.5
						microseconds at the receiving
						terminal.
2
	20		DATA 1		IN	These signals represent information
3	21		DATA 2		IN	of the 1st to 8th bits of parallel data,
4	22		DATA 3		IN	respectively. Each signal is at HIGH
5	23		DATA 4		IN	level when data is logical 1 and LOW
6	24		DATA 5		IN	when it is logical 0.
7	25		DATA 6		IN
8	26		DATA 7		IN
9	27		DATA 8		IN
10					OUT	About a 12-microsecond pulse. LOW
	28		ACKNLG
						indicates that data has been received
						and that the printer is ready to accept
						more data.
11	29		BUSY		OUT	A HIGH signal indicates that the
						printer cannot receive data. The
						signal goes HIGH in the following
						cases:
						1) During data entry (ea. char. time)
						2) During printing
						3) When off line
						4) During printer-error state
12	30		PE		OUT	A HIGH signal indicates that the
						printer is out of paper.
13			SLCT		OUT	Pulled up to +5 volts through 3.3K
						ohm resistance.

8-10 Technical Specifications