Epson 8900 Series manual Parallel Interface Signal Descriptions

	Parallel Interface Signals
Signal	Name	Pin	Return	Source
STROBE-	Data strobe	1	19	Host
DATA1	Data bit 1	2	20	Host
DATA2	Data bit 2	3	21	Host
DATA3	Data bit 3	4	22	Host
DATA4	Data bit 4	5	23	Host
DATA5	Data bit 5	6	24	Host
DATA6	Data bit 6	7	25	Host
DATA7	Data bit 7	8	26	Host
DATA8	Data bit 8	9	27	Host
ACK-	Acknowledge	10	28	Printer
BUSY	Printer busy	11	29	Printer
PE	Paper empty	12	30	Printer
SLCT	Select	13		Printer
LGND	Logic ground	16
CGND	Chassis ground	17
PARVCC	+5 volts dc*	18		Printer
INIT-	Initialize	31		Host
FAULT-	Fault	32		Printer
GND	Ground	33
VFIN	Verify in	34		Host
VFOUT	Verify out	35		Printer

Notes: Pins 14, 15, and 36 are not used.

*+5vdc supplied through 51 ohm resistor.

Parallel Interface Signal Descriptions

As indicated in the preceding table, the data signals and some of the control signals require both a signal line and a return line. This arrangement provides efficient, trouble-free operation and minimizes electrical noise on the signal lines.

Some parallel interface signals are active when low, as indicated by a hyphen (-) attached as a suffix to the signal name. All other signals (except the data signals) are active when high. Since the data transferred over the data lines consists of binary ones and zeros (highs and lows), the state of these lines depends on the data being sent. The following paragraphs describe the parallel interface signals.

Communication Interfaces 10-7