Xref: utzoo comp.sys.att:2904 comp.dcom.modems:1653
Path: utzoo!utgpu!water!watmath!clyde!att-cb!att-ih!pacbell!ames!mailrus!umix!b-tech!m2-net!cmr
From: cmr@m2-net.UUCP (Chuck Rader)
Newsgroups: comp.sys.att,comp.dcom.modems
Subject: Re: AT&T 4024C & Hayes 2400
Summary: Try changing S7 and S9 registers on Hayes
Keywords: 4024, Hayes, carrier, S-register
Message-ID: <1623@m2-net.UUCP>
Date: 30 Mar 88 00:25:10 GMT
References: <356@mancol.UUCP>
Reply-To: cmr@m-net.UUCP (Chuck Rader)
Organization: University of Detroit, Computer Services
Lines: 23

In article <356@mancol.UUCP> samperi@mancol.UUCP (Dominick Samperi) writes:
>I just installed an AT&T 4024C modem for use with a 3B2/300, and it seems
>to work fine, except for one problem: the 4024 modem must be called 2-3
>times before it sends a carrier that my Hayes 2400 understands. Most of the

The problem may really be on the Hayes side.  We've had problems with Hayes
1200 calling 2400 bps modems because the answering modem often cycles 
through several carrier tones either too quickly or too slowly and the Hayes
gives up before it recognizes the tone.

Try increasing the value of Hayes register S7 (seconds to wait for carrier)
and decreasing the value of S9 (1/10 seconds that carrier must be on 
continuously before being recognized).  The defaults on Hayes 1200 are S7=30
and S9=6.  I'm not sure if the 2400 defaults are the same.
S9 is the more likely culprit.

I haven't used the 4024 or the Hayes 2400, but the S-register changes are worth
a try.  They do help on Hayes 1200.
-- 
Chuck Rader, Manager, Computer Technical Services, University of Detroit
voice: 313-927-1349   internet: cmr%m-net@umix.cc.umich.edu         
  fax: 313-927-1011   uucp:  {rutgers|uunet}!umix!m-net!cmr                  
I don't worry 'bout a thing 'cause I know nothin's gonna be all right.