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From: dmt@hocsl.UUCP
Newsgroups: net.micro
Subject: Re: What is RS-432??? - (nf)
Message-ID: <115@hocsl.UUCP>
Date: Tue, 10-Apr-84 08:26:19 EST
Article-I.D.: hocsl.115
Posted: Tue Apr 10 08:26:19 1984
Date-Received: Wed, 11-Apr-84 05:38:40 EST
References: <4970@lanl-a.UUCP>
Organization: AT&T Information Systems Labs, Holmdel NJ
Lines: 18

It is my understanding that the "new" standards (RS-422, -423,
& -449) have separated the functional specifications from
the electrical. The "old" RS-232 had both functional and electrical.
Let's try a picture, and hope my facts are right:

           ----OLD----       ----------------NEW---------------------------
             RS-232            RS-422         RS-423         RS-449

FUNCTIONAL  25 leads              -              -          37 leads

ELECTRICAL Unbalanced to      Balanced to   Unbalanced to        -
             20 Kbps            ~1Mbps        >20 Kbps

Thus, a 25-pin subset of RS-449 with drivers meeting RS-423 would be
compatible with RS-232.
				Dave Tutelman
				AT&T IS - Holmdel
				...!hogpc!hocsf!hocsl!dmt