Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!cs.utexas.edu!uunet!nuchat!moray!siswat!buck
From: buck@siswat.UUCP (A. Lester Buck)
Newsgroups: comp.unix.i386
Subject: Re: Parallel I/O Port
Message-ID: <444@siswat.UUCP>
Date: 25 Aug 89 16:52:18 GMT
References: <1609@cbnewsl.ATT.COM>
Organization: Photon Graphics,  Houston
Lines: 19

In article <1609@cbnewsl.ATT.COM>, raj@cbnewsl.ATT.COM (Richard A. Johnson) writes:
> 
> I have an AT&T 6386 WGS running UNIX.  I want to use the parallel I/O
> port to communicate with devices other than printers.  One example
> would be to connect 2 PCs together using the parallel port on each PC.

The best discussion of PC parallel ports I have ever seen was in an
article in MicroCornucopia magazine, #38, Nov-Dec 87, p.28, entitled
"Magic in the Real World" by Bruce Eckel.  He gives a complete and
detailed schematic for a $19 parallel port card, shows the small
hardware modification necessary to make it bidirectional, and covers
the tricks of using the status lines to transmit data without hardware
modifications.  You won't be able to use the standard lp driver to
transfer data bi-directionally.  The article also gives Turbo C code
for a TSR that manipulates the parallel port.  You might use this
as the basis for a new lp driver for data transfer.

-- 
A. Lester Buck		...!texbell!moray!siswat!buck