Path: ns-mx!uunet!stanford.edu!agate!darkstar!ucscb.UCSC.EDU!unknown
From: unknown@ucscb.UCSC.EDU (The Unknown User)
Newsgroups: comp.sys.apple2
Subject: Re: Modem help again!  :)
Message-ID: <22385@darkstar.ucsc.edu>
Date: 17 Oct 91 23:53:43 GMT
References: <9110171510.AA12541@apple.com>
Sender: usenet@darkstar.ucsc.edu
Organization: University of California, Santa Cruz; Open Access Computing
Lines: 66


In article <9110171510.AA12541@apple.com> QXN141@URIACC.URI.EDU (Andy) writes:
>    Could someone with a MNP modem (either 2400 or 9600 baud) that has
> gotten it to work send me the pinouts for the way their modem cable is
> wired.  Also tell me what Comm software you have gotten to work correctly
> with MNP on and off and so on.  Thanks much.

        Well, I use ProTERM 2.2, and now use it at 9600 baud without
either v.42bis standard on (MNP or LAPM).  ProTERM 3.0 will support
hardware error correction.

        Here is a letter I got from someone on the same topic. The quoted
areas are things I said.  I don't vouch for the validity of this, but
it seems to make sense. (I may call up InSync to make absolutely sure these
are the connections they are presuming, but this seems right).

        Note this stuff is "Mac" info. The Mac and GS' serial ports are
identical, externally and internally, as far as I can tell.


___BEGIN QUOTED MESSAGE__
>         No offense, but are you -sure- it's "true" hardware handshaking?
> (That is, RTS to RTS, CTS to CTS).

   Pins 1 and 2 are used as RTS and CTS on the mac.

   Yes.  I use one with my HST dual standard.  My sister uses one with her HST.
My local BBS (which has 8 lines at HST or above) recommends this cable for use.
We have hundreds of members using 9600bps-and-above modems.

>         Also, WHAT pin IS RTS on the Mac MINI DIN 8 connector? (My computer's
> connectors are IDENTICAL internally and externally)

According to January 90 MacUser, the mac hw hsk cable looks like this:

      mini-DIN 8           RS-232C
         1                   4  (to pin 20 on conventional non-hsk cables)
         2                   5
         3                   2
         4                   7
         5                   3

>         I see that one pin is "received uninverted at SCC's /CTS and /TRxC"..
> So that means that that pin is CTS (although inverted improperly??).

     Pins 1 and 2 are used for RTS and CTS respectively.  Note that a HW HSk
cable can never "drop DTR", so you have to set the modem to "Hold DTR High"
(a dip switch on my HST d/s).

> thanks again for the info though.  In some ways I want to figure this out
> myself before I make/buy a cable. I don't want to buy a cable and have it
> end up being "Fake" handshaking. (that is, send one of the other handshaking
> signals instead of RTS)

    There is no such thing as "fake" handshaking on the mac.  Conventional
cables are based on the assumption that DCE-DTE speed = DTE-DTE speed.  They
use pin 1 on the mac to signal DTR.  They're not attemptng to handshake at
all.

    You can only use a hardware handshaking cable with s/w that knows about
hardware handshaking.  Usually there is a check box in the Modem Setup dialog.
If your software cannot handle it, then you'll have to use a conventional
cable and strap your modem down during uploads (so that DTE-DCE = DCE-DCE).
-- 
/unknown@ucscb.ucsc.edu       Apple IIGS Forever!        CHEAP CD info-mail me\
\WANT to help get INFOCOM GAMES RERELEASED & ULTIMA VI GS written? -  mail me./