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From: russotto@eng.umd.edu (Matthew T. Russotto)
Newsgroups: comp.sys.mac.misc
Subject: Re: Wiring for hayes modem w/handshaking
Message-ID: <1991Mar24.191816.11089@eng.umd.edu>
Date: 24 Mar 91 19:18:16 GMT
References: <27EB1B0B.3468@ics.uci.edu> <1991Mar24.082806.14851@news.arc.nasa.gov>
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Organization: College of Engineering, Maryversity of Uniland, College Park
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In article <1991Mar24.082806.14851@news.arc.nasa.gov> ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:

>The pinout given by Cieman has a different klooch, namely the modem
>sees (via its DTR input) that, whenever it asserts its RTS output, the
>Data Terminal (the Mac) is ready.

Unfortunately, Pin 4 is TO the modem-- so what the modem sees is that whenever
the mac is ready to recieve (CTS asserted), the Data Terminal is ready.  This
is bad, as I pointed out in another post.

>Interestingly enough, the NeXT's serial port is RS-423, rather than
>RS-422, as in the Mac. The former supports the four independent handshaking
>signals.
  Pin 20
(Mac side) should go to pin 4 (modem side) ONLY-- not pin 20 (modem side)

If you like, with the regular cable (not the adaptor), connect pin 7 (mac
end) to pin 8 (modem end), to allow carrier detect on the general-purpose
input (if your software supports it-- most doesn't)
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.