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From: holtzman@mit-amt.MIT.EDU (Henry N. Holtzman)
Newsgroups: net.dcom
Subject: Re: Office networking ala RS-232
Message-ID: <191@mit-amt.MIT.EDU>
Date: Fri, 16-May-86 13:20:41 EDT
Article-I.D.: mit-amt.191
Posted: Fri May 16 13:20:41 1986
Date-Received: Sun, 18-May-86 14:41:56 EDT
References: <532@gould9.UUCP>, <11620@amdcad.UUCP> <6674@utzoo.UUCP> <145@ryesone.UUCP>
Organization: MIT Media Lab, Cambridge, MA
Lines: 18
Summary: Dont just wire TD and RD!!!

In article <145@ryesone.UUCP>, mason@ryesone.UUCP (Dave Mason) writes:
> I had a client once who only used 2 lines for terminals (TD,RD), and depended
> on the building grounds to be close enough (it worked).  We use 4 wires
> (TD,RD,SG,DTR) for our terminals, and do basically what henry@utzoo suggested
> for straps except that our machine needed some strange jumpers (computer end).

I also once knew someone who counted on building ground.  Then he went
to put in a different terminal, and his rd,td became a loop at both
ends.  (Both the terminal and computer would get an echo of what it typed,
but it wouldn't make it through to the other.) It was funny to watch,
but not funny to re-wire.

The moral is:  Unless you are going to lock yourself into one set of
hardware for the rest of your life, stay at least close to the specs.
Don't just experiment with your equipment and then try to get away
with what seems to work, but shouldn't.

-Henry