Printer User Manual

Page 23
3.2 MPP SERIES - 8 BIT PARALLEL INTERFACE
The Parallel Interface signals for the MPP printer series are terminated on a 25 pin IBM PC
parallel printer output type connector located on the front panel of the printer.
The table below lists the Parallel Interface signals and the connector pinouts. A (/) before a
signal name indicates the signal is ACTIVE LOW; otherwise, the signal is ACTIVE HIGH.
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PIN# SIGNAL NAME DIRECTION FUNCTION
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1 /STROBE INPUT DATA READY FROM HOST
2 DATA 1 INPUT DATA BIT 1 FROM HOST
3 DATA 2 INPUT DATA BIT 2 FROM HOST
4 DATA 3 INPUT DATA BIT 3 FROM HOST
5 DATA 4 INPUT DATA BIT 4 FROM HOST
6 DATA 5 INPUT DATA BIT 5 FROM HOST
7 DATA 6 INPUT DATA BIT 6 FROM HOST
8 DATA 7 INPUT DATA BIT 7 FROM HOST
9 DATA 8 INPUT DATA BIT 8 FROM HOST
10 /ACK OUTPUT RECEIVE ACKNOWLEDGE FROM PRINTER
11 BUSY OUTPUT BUSY OUTPUT FROM PRINTER
12 COMMON SIGNAL COMMON
13 4.7K PULL UP TO VCC
14 /PAPER-FEED INPUT PAPER FEED REQUEST FROM HOST
15 4.7K PULL UP TO VCC
16 NO CONNECTION
17 SELECT-IN INPUT SELECT PRINTER FROM HOST - OPTIONAL
18 THRU 25 SIGNAL COMMON
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A minimum of 12 connections are required for the parallel interface operation (pin 1 through 12).
3.2.1 MPP SERIES - PARALLEL INTERFACE OPERATION
Pin #1 of the Parallel Interface connector carries the </STROBE> signal from the host
computer to the printer. This signal is held at TTL HIGH level normally, and lowered by
the computer when the data is ready for the printer. The fact that the signal went low is
latched by the printer control card and the processor is interrupted to read, validate,
and save the data received.
Also, the <BUSY> signal (Pin#11) is set to indicate that the printer is busy reading data
received.
Upon saving the received data, the printer lowers </ACK> (Pin #10) to acknowledge
that the data has been received, and lowers the BUSY signal.