Path: utzoo!utgpu!watmath!clyde!att!ttrdc!ttrde!pfales
From: pfales@ttrde.UUCP (Peter Fales)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Using the printer port for input
Summary: Sorry, can't be done
Message-ID: <816@ttrde.UUCP>
Date: 11 Jan 89 14:53:34 GMT
References: <704@krafla.rhi.hi.is>
Organization: AT&T, Skokie, IL
Lines: 21

In article <704@krafla.rhi.hi.is>, frisk@rhi.hi.is (Fridrik Skulason) writes:
> I need to connect a set of eight switches to my PC. The most simple way 
> to do it seems to be connecting them to the parallel port, and using it
> as input port instead of output. 
> 
> My question is: Does anyone have a code fragment (in C, assembler or
> whatever) for changing the port into an input port?

Sorry, the standard PC parallel port hardware is not capable of being
used as an input port no matter how clever your code is.  

There was an article a few months ago in Steve Ciarcia's "Circuit Cellar
INK" magazine on a simple hardware modification to correct this
problem.  It requires cutting a trace, adding a wire, and is pretty
simple if you are good at tracing out paths on a circuit board.

-- 
Peter Fales			AT&T, Room 2F-217
				200 Park Plaza
UUCP:	...att!ttrde!pfales	Naperville, IL 60566
Domain: pfales@ttrde.att.com	work:	(312) 416-5357