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From: david@bacchus.esa.oz.au (David Burren)
Newsgroups: comp.dcom.modems
Subject: Re: baud rate weirdness
Message-ID: <863@bacchus.esa.oz.au>
Date: 13 Dec 90 01:40:10 GMT
References: <125@marilyn.UUCP>
Organization: none
Lines: 40

In <125@marilyn.UUCP> shawn@marilyn.UUCP (Shawn P. Stanley) writes:

>I have written connection-handling software which begins the process of
>waiting for a call/connect first by setting the serial port to the high
>(2400) baud rate for the modem, then sends an "AT" sequence (these are
>Hayes compatible modems) so that the modem knows the baud rate of the
>serial port and can then answer with a CONNECT message at the serial
>port's rate before switching to the caller's rate.

AAARRRGGGGHHHHHH!!!!!

"baud rate"?  Urgle.  Your grammar is _shocking_.
	baud	=> signal change rate
	bps	=> bit rate

"signal change rate rate"????

It's an easy mistake to make, but it's one of my pet flames, so please
excuse me if I fly off the handle.
In most cases where people use "baud rate" they'd be better off using
"bit rate" as it's more correct in several ways.  ("more correct"? sigh :-)


>With two modems that I know of, a 2400-baud caller will find that the
>answering modem connects at 1200 baud.  300 baud calls are fine; 1200
>baud calls are fine.  But 2400-baud calls become 1200-baud connects.

I don't have an answer, but I've noticed the same problems with some
modems.
A Maestro ZXR when calling a v.32 modem or a Maestro 24DO (v.22bis/MNP)
connects at 1200 bps unless ATB8 is issued beforehand.


>What could explain this behavior?

I'd be interested in any responses you get.
_____________________________________________________________________________
David Burren [Athos]                          Email: david@bacchus.esa.oz.au
Software Development Engineer                 Phone: +61 3 819 4554
Expert Solutions Australia, Hawthorn, VIC