Interfaces
8-6
The following illustration shows the pin assignments for connecting the 25-pin
connector to the 36-pin connector. The symbol * indicates an active low signal.
The parallel interface consists of an 8-bit parallel data bus with the following
characteristics:
• Uses 17 of the 36 positions on the printer connector, as follows:
– The host system controls 12 lines, which it uses to send data and com-
mands to the printer.
– The printer controls five lines. The printer uses two lines to notify the com-
puter when data is transferred successfully and three lines to report printer
status.
• Controls synchronization with an externally supplied STROBE* pulse.
• Controls data flow control with BUSY and ACKNLG* signals. Does not carry
out data transfer by ignoring the BUSY or ACKNLG* signal. (The system can
carry out data transfer to the printer only when the level of the BUSY signal is
low and after confirming the ACKNLG* signal is high.)
Computer
Side
25-Pin
Connector
Printer
Side
36-Pin
Connector
Note: Lexmark IEEE 1284 compliant cables
are supported up to 20 feet. Cable lengths
greater than 20 feet are not supported. The
cable drawing to the left is a functional
representation of the Lexmark cables; it does
not reflect correct pairing of leads or unused
pairs.
1284-B
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