Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!sun-barr!decwrl!ucbvax!PICA.ARMY.MIL!ekijak
From: ekijak@PICA.ARMY.MIL ("Edmund S. Kijak", IMD-SIAS)
Newsgroups: comp.sys.atari.8bit
Subject: SIO to RS-232 pinouts
Message-ID: <8912211338.aa25371@COR3.PICA.ARMY.MIL>
Date: 21 Dec 89 18:38:55 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
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>Could someone post or e-mail me a description of which pins of each connector
>are connected together?  i.e. rs232-----SIO

>something like RS232 pin 2 to SIO pin?
	       RS232 pin 3 to SIO pin?
	       RS232 pin 7 to SIO pin?  (this one is ground, should be easy to
					 guess!)
>thanks in advance (assuming that this makes any sense!)
>I'm asumming that it's just a matter of using nothing else than wire in the
>above!
>------------------------------
     If my memory serves me correctly, the SIO pins are

                     gnd gnd  +5vdc
                      |  |   /
                   o  o  o  o  o
                 o  o  o  o  o  o
                   /    \
      Serial Data In     Data Out

     The serial data pins put out and receive TTL levels, i.e., zero to 5 volts.
RS-232 requires -5 to +5 volts and so there may be more than just a wire
connection required.  I have used a Maxim MAX232 chip to convert from TTL to
RS-232.  I don't recall which pins on the RS-232 connector are data in and data
out, but that info should be easy to get.