From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <3F23D4EF.4090705@arrl.net>
From: John DeGood <nu3e@arrl.net>
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To: 9fans@cse.psu.edu
Subject: Re: [9fans] Anyone awake?
References: <3F238F58.7000202@ameritech.net>
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Date: Sun, 27 Jul 2003 09:34:39 -0400
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Your Mac RS-232 port has typical voltage swings from -12 to +12 volts.
Your PC parallel port is TTL logic with voltage swings from 0 to +5
volts.  To electrically connect the 2 together you'd need a TTL ->
RS-232 transceiver, otherwise you may smoke the PC's parallel port.
Even if it doesn't smoke, it probably won't work without a transceiver.
And then there's the matter of emulating a UART on the Plan 9 parallel
port side, but of course that's easy because it's only software. :-)

If you want to save yourself a lot of grief, construct or buy a DB25F to
DB9F null modem cable.

John

northern snowfall wrote:

> Hey all,
>     I went to a computer show tonight and found a
> MiniDIN8 -> DB25 cable for a Macintosh. Since my partner-
> in-crime is away mountain climbing, I have no idea how
> to set this up.
>
>     Google searches only reveal documentation on
> setting up serial consoles on the server side, not the
> client side. I'm planning on using an IBM PC (either plan9
> or UNIX) as the terminal. Can anyone give me any pointers
> on how to set this up?
>
>     Since the cable is DB25, I'm lookin' at using my
> parallel port. Is that even possible, to simulate a serial
> console over the parallel? Or, am I looking at using another
> adapter to connect the parallel to serial?
>
> Thanks, as always,
>
> Don
>
> http://www.7f.no-ip.com/~north_
>
>