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Posting-Version: version B 2.10 5/3/83; site umcp-cs.UUCP
Path: utzoo!linus!decvax!harpo!seismo!rlgvax!cvl!umcp-cs!zben
From: zben@umcp-cs.UUCP
Newsgroups: net.dcom
Subject: Re: Two wire RS232 - WARNING
Message-ID: <3629@umcp-cs.UUCP>
Date: Sun, 6-Nov-83 13:11:30 EST
Article-I.D.: umcp-cs.3629
Posted: Sun Nov  6 13:11:30 1983
Date-Received: Tue, 8-Nov-83 03:12:06 EST
Organization: Univ. of Maryland, Computer Science Dept.
Lines: 18

We have used a 4-wire RS232 connection scheme on the dinosaur (UNIVAC-1100)
for years now.  For economy we used a Radio Shack non-modular 4-post plug
and jack set (remember them) that was much cheaper than DB25s.  The four
wires connected are transmit data, receive data, signal ground, and data
terminal ready (which went only to a LED on the patchboard so you wouldn't
accidently pull an in-use line).  The patchboard has long since been
replaced by a Gandalf PACX switch.

You are lucky it was only the interface chip (1489).  Then again it was
designed to sacrifice itself in just this case.  Sometimes it is the only
chip socketed in a design (guess why).  Before I realized this I always
wondered why UARTs didn't just speak RS232 levels...

That technician should be yelled at a bit.  There have been stories here
on the net about techs smoking while bending over an open disk drive.
Shudder.  Where do we get these people?

Ben Cranston      ...seismo!umcp-cs!zben       zben@umd2.ARPA