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From: jade@hydra.unm.edu (Eric Jaderlund)
Newsgroups: comp.sys.mac.hardware
Subject: Need Help with a Mac 512K and a Hayes type modem.
Message-ID: <1990Aug30.153116.24276@ariel.unm.edu>
Date: 30 Aug 90 15:31:16 GMT
Sender: usenet@ariel.unm.edu (USENET News System)
Organization: University of New Mexico, Albuquerque
Lines: 46

My girlfriend recently bought a used CTS 21AHC 1200buad modem at a steal
of a price and I'm trying to get it to work on her Mac 512K.  I am having
some problems that I hope someone can help with.

First there was the struggle with the cable but I think I have made it
correctly, I wired it as follows:

     Mac(9pin)  Modem(25pin)  
     ---------  -----------
         1    to     1
         3    to     7
         5    to     2
         7    to     5
         9    to     3

Is this right?

My problems are 3-fold

1) When I first turn it on the modem starts spitting characters to the computer
non-stop.   After playing for about 10 minutes it settles down and talks nicely
to the computer (I am using Red Ryder, by the way).  AT gives an 'OK' response
and I can check and set all the registers.  But if the modem is off for a
while I have to go through the 10 minof garbage before it works.

2) If I try an analog loopback test (this should echo typed characters back
to the screen) it goes into that mode and once again out comes the garbage
characters non-stop unit I give the interrupt comman (+++) then it stops and
goes back to normal.

3) The biggest problem is that it wont dial.  An 'AT DT', or any other dial
command, spits a  line or two of garbage and then says 'NO DIALTONE'.  The
phone cables seem fine and the regular phone works OK when plugged into the
modem.  Also I can hear the little realy 'click' after the AT DT command and
click again a few seconds later after it cant detect the dialtone.

I would suspect a hardware problem but the person who we got it from used
it on his IBM-XT without any trouble.

Any ideas???? All help appreciated.

Thanks,
---------------------------------------------------------------------------
Eric Jaderlund
jade@hydra.unm.edu
Univ. of New Mexico