Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!hayes!tnixon
From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: Controlling answer tone sequence
Message-ID: <3885.27f003d8@hayes.uucp>
Date: 27 Mar 91 02:30:48 GMT
References: <22HgZ1w163w@aegis.or.jp>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 32

In article <22HgZ1w163w@aegis.or.jp>,
davidg%aegis.or.jp@kyoto-u.ac.jp (Dave McLane) writes: 

> Somebody has suggested that it is only Japanese-made modems that 
> change speed on call as well as answer. The USRobotics I have 
> doesn't change on call but all the Japanese modems I've tested do
> (Aiway, Omron, Epson). What about other US-made modems, do they
> change speed on call as well as on answer?

To the best of my knowledge, virtually ALL modems will, when being 
used to originate a call, change speeds to match the capabilities of 
the answering modem, unless they've been specifically configured to 
disable this feature.  All Hayes modems do.

Older (pre-V-series) Hayes modems behaved like your USR -- once they 
answered a call at a lower speed, that speed became the maximum for 
future calls if the modem didn't receive a command from the DTE at a 
higher speed in the meantime.  We learned, however, about systems 
like Unix and other applications that CAN'T issue commands to the 
modem between calls, and so changed the behavior of our modems so 
that between calls they switch back to the speed of the last AT 
command issued rather than the speed at which the last call 
connected.  Many other manufacturers have done the same thing, but 
not all.  Of course, with the V-series modems, you can set an 
S-register to specify the maximum connect speed rather than it being 
dependent on the AT command speed.

-- 
Toby Nixon, Principal Engineer    | Voice   +1-404-840-9200  Telex 151243420
Hayes Microcomputer Products Inc. | Fax     +1-404-447-0178  CIS   70271,404
P.O. Box 105203                   | UUCP uunet!hayes!tnixon  AT&T    !tnixon
Atlanta, Georgia  30348  USA      | Internet       hayes!tnixon@uunet.uu.net