Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!pt.cs.cmu.edu!b.gp.cs.cmu.edu!ralf
From: ralf@b.gp.cs.cmu.edu (Ralf Brown)
Newsgroups: comp.sys.ibm.pc
Subject: Re: CCITT V.22 Mode
Keywords: 1200 bps, compression?, modem
Message-ID: <9806@pt.cs.cmu.edu>
Date: 4 Jul 90 03:46:24 GMT
References: <2NiRL1w162w@valnet>
Organization: Carnegie-Mellon University, CS/RI
Lines: 15

In article <2NiRL1w162w@valnet> herrj@valnet (Jonathan R. Herr) writes:
}manual to my Databyte Modem 1200 looking at the AT command summary and
}ran across the B/B0 command.  What exactly does this do?  Does someone
}I guess the questions should really be Does this run a compression mode
}of some sort to increase transmission speeds?

My understanding is that the Bell 212 and CCITT V.22 standards are identical
except for the initial connect handshake.  The B command specifies which
handshake to use.  If I remember correctly, Bell 212 uses a simple steady
tone, while CCITT uses a series of training tones to guage line quality.
-- 
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_How_to_Prove_It_ by Dana Angluin  23. proof by semantic shift: some standard
    but inconvenient definitions are changed for the statement of the result.