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From: tnixon@hayes.uucp
Newsgroups: comp.dcom.modems
Subject: Re: PEP vs. v.32
Message-ID: <3820.27ce2ea5@hayes.uucp>
Date: 1 Mar 91 10:36:21 GMT
References: <1991Feb27.185340.3897@shaman.com> <1991Feb28.050506.7297@watdragon.waterloo.edu>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 46

In article <1991Feb28.050506.7297@watdragon.waterloo.edu>,
ccplumb@rose.uwaterloo.ca (Colin Plumb) writes: 

> Toby Nixon posted a while ago that Telebit was going to present a paper
> to the V.fast commitee about a PEP-like 28,000 baud full duplex modem.
> There were other proposals in the same wonderful performance range for
> the meeting... I wonder what happened?

Since you asked...

Telebit didn't come through.  They did present a fairly detailed 
technical paper (the kind you'd see in IEEE Transactions on 
Communications, full of formulas and such) on how to do echo
cancellation in a multicarrier modem, but no details on their
proposal and no testing results.  Codex, on the other hand, 
presented a very detailed and specific proposal on a single-carrier 
scheme that goes up to 24,000bps on most phone lines in the US, and 
they included extensive and detailed testing results to prove it.  
The technology in the Codex modem to improve performance allows it 
to transmit between 16,800 and 19,200 on the same lines that V.32bis 
can just barely send 14,400.  Pretty good!  I _still_ want to hear 
what Telebit has to say, but it looks like it will be April or later 
before we see any details.

Also, it was fascinating that Intelligent Modem Corporation (Forval) 
has now stepped forward with a counter-proposal to Telebit for a 
_different_ multicarrier scheme (and we all thought only Telebit did 
those kind of modems!).  I actually like what I've heard about the 
IMC proposal better than Telebit -- higher throughput, easier to 
implement, etc.  But, again, they didn't lay it all out on the 
table and didn't have any testing results, but gave a "conceptual" 
presentation.

There were several other contributions from Racal-Milgo, IBM Europe, 
and others, giving specific details about the single-carrier 
approach.

We should get a lot more contributions for the meeting of Study 
Group XVII at the end of April.  Remind me again the first week of 
May, and I'll try to summarize for you what happened there.

-- 
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