Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!oliveb!mipos3!omepd!inteloa!hah
From: hah@inteloa.intel.com (Hans A. Hansen)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 3_wire fix
Keywords: ground to the room
Message-ID: <5027@omepd.UUCP>
Date: 10 Oct 89 00:15:40 GMT
References: <7225@thor.acc.stolaf.edu>
Sender: news@omepd.UUCP
Reply-To: hah@inteloa.UUCP (Hans A. Hansen)
Organization: Intel Corp., Hillsboro, Oregon
Lines: 38

In article <7225@thor.acc.stolaf.edu> henning@thor.acc.stolaf.edu (Mark D. Henning) writes:
$
$Here is my promised posting of the solution to my 2 wire serial
$problem.  I got two answers (one of them by several people).
$
$The first answer would be very expensive and unprofitable.

Stuff deleted.

$
$The other solution I have posted below.  It is very good, however, I
$am unsure whether or not it works, because I finally convinced
$telecommunications to let me rewire the jacks (the 4 wire had been
$run, but only 2 connected.)
$
$Anyway, Thanks again to all who sent me the ideas.
$
$^Mark,
$^You actually have three wires available.

WARNING *****

This solution while sounding good will give you nothing but grief!

This is a very noisy, both in terms of signal quality and RF emissions,
answer to your problem.

You said that you have 4 wires available... use them.  You will need a
good ground return for both TX and RX signals.  Twisted pair wires also
offer common mode noise rejection and RF emissions reduction.

If you are still not convinced then I suggest that you invest in RS-232
transceivers... you'll need them.  To really solve this with this type of
circuit you will need opto-isolators.

		Hans

More stuff deleted.