Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bionet!ames!lll-winken!uunet!iscuva!jimc
From: jimc@iscuva.ISCS.COM (Jim Cathey)
Newsgroups: sci.electronics
Subject: Re: Yet another request for Opto-Iso. recommend
Message-ID: <2570@iscuva.ISCS.COM>
Date: 17 Jul 89 18:47:16 GMT
References: <20380@cup.portal.com> <762@xroads.UUCP>
Organization: ISC Systems Corporation, Spokane WA
Lines: 23

In article <762@xroads.UUCP> wiz@xroads.UUCP (Mike Carter) writes:
>> be a good idea.  Can anyone recommend a good cheap opto-isolator for use
>> with RS422 from a Macintosh?  What should put across the RS422 signal,
>
>Mark:
>If you're talking about (for instance) the Mac 512K(E) etc the 9-pin
>communications port is NOT RS422. It's RS232C ..just has a mini DB-9
>connector (after all, why waste a DB-25 when all you need is a DB-9?)

The Macintosh is indeed RS-422 -- that's how they're able to get 230.4 kbits
out for Appletalk.  For very short cables you can just hook 422 to 232
and get away with it, but not always.  Most folks don't seem to have problems
with the fake RS-232 of the Macintosh.  I for one applaud their decision.
RS-232 is a hunk of #^#$% that should have died out long ago.

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