Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!sun!pitstop!sundc!seismo!uunet!van-bc!sl
From: sl@van-bc.UUCP (pri=-10 Stuart Lynne)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Parallel Printer Port
Keywords: Input
Message-ID: <1889@van-bc.UUCP>
Date: 22 Sep 88 19:39:38 GMT
References: <8579@watdragon.waterloo.edu>
Reply-To: sl@van-bc.UUCP (pri=-10 Stuart Lynne)
Distribution: na
Organization: Wimsey Associates, Vancouver, BC.
Lines: 25

In article <8579@watdragon.waterloo.edu> jeboritz@watdragon.waterloo.edu (J. Efrim Boritz) writes:
>
>Is it possible to use the parallel printer port for input? From reading
>the Tech. Ref. Manual, I get the idea that having an external device drive
>the data pins is a no-no. Is this the case?
>
>If possible, I want to write a program to receive what the printer is getting
>(from another computer over a network) to track a problem we are having.
>I would appreciate any pointers (or even code?!?) from anyone with some
>knowledge in this area.
>

You can't do what you want to do. But you can read some data via the
parallel port. Basically there are about 4 status bits that can be read,
with an appropriate cable you can swap 4 of the data bits and the 4 status
bits. Then each side can send nibbles (4 bits) of data which can be received
at the far end.

This is how some of the file transfer products work. It's actually quite
fast, basically dependant on how fast each end can raise and lower the
handshake lines.


-- 
Stuart.Lynne@wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl     Vancouver,BC,604-937-7532