Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!ogccse!blake!richg
From: richg@blake.acs.washington.edu (Richard Goldfinder)
Newsgroups: comp.sys.atari.8bit
Subject: Re: hooking up an 850 to my suprea modem
Summary: pinouts for 850 ports
Keywords: 850, pinouts
Message-ID: <3371@blake.acs.washington.edu>
Date: 25 Aug 89 17:25:34 GMT
References: <8908251306.AA26259@ucbvax.Berkeley.EDU>
Reply-To: richg@blake.acs.washington.edu (Richard Goldfinder)
Organization: University of Washington, Seattle
Lines: 23

In article <8908251306.AA26259@ucbvax.Berkeley.EDU> FNMELNIK@WEIZMANN.BITNET (Ofer Melnik) writes:
>
>I recently purchased a supra 2400 bps modem. I am trying to hook it up using
>an 850 interface that I got second hand..problem is that I dont have the
>cable needed to connect the 850 ( 9 pin serial ) to the modem ( 25 pin
>Rs-232)..does anyone have the pin layout for this job ..c i was loking
>through some guide and there is no set standard for a 9pin rs232...

The pins on port #1 are:

1 DTR (Data Terminal Ready)
2 CRX (Carrier Detect, CD)
3 SD (Send Data)
4 RD (Receive Data)
5 GND (Signal Ground)
6 DSR (Data Set Ready)
7 RTS (Request To Send)
8 CTS (Clear To Send)

Ports 2 and 3 are the same, except that they don't have 2, 7 or 8 connected.
Port 4 has 1,3,4,5, and 7 connected, plus a -8v connection at pin 9.

Source: pages 91-93 of "Atari 850 Interface Module Operator's Manual"