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From: casey@gauss.llnl.gov (Casey Leedom)
Newsgroups: comp.dcom.modems
Subject: Re: Abstracts of papers for upcoming V.fast Meeting
Message-ID: <89753@lll-winken.LLNL.GOV>
Date: 18 Jan 91 20:01:25 GMT
References: <3736.2796d6db@hayes.uucp>
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Reply-To: casey@gauss.llnl.gov (Casey Leedom)
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| From: tnixon@hayes.uucp (Toby Nixon)
| 
| [[Abstracts of all sorts of interesting new modem technology proposals.]]
| 
| The meeting will be lively, filled with fascinating discussions and
| arguments over the various proposals and papers.  Wish you could all be
| there!  It will certainly be interesting to finally see Telebit's
| proposal for echo cancellation in multicarrier modulation and Codex's
| proposal for single-carrier 24000 bit/s modulation (that's synchronous
| bit rate, without data compression, folks).

  I wish I could be there too even though I wouldn't understand most of
the hard core engineering and signal processing issues.  (Just a software
geek.)  But two questions pop into my mind immediately:

    1.	My [naive] guess would be that multi-carrier technology would
	be a lot better than single-carrier because of multi-carrier's
	ability to adapt around bad spots in the frequency response
	spectrum.

	Since Hayes is arguing in favor of single-carrier technology
	can you give us a brief on what the arguments are in favor
	of each?

    2.	With 24Kbps, V.42bis could offer up to 96Kbps and may typically
	deliver 48Kbps.  Obviously we'll want to run our interfaces
	near that 96Kbps in order to give V.42bis a chance to deliver
	all that it can.

	What kind of interfaces are we going to use that will operate at
	that rate?  I don't think that we can expect to push that old
	war hound EIA-232 that far.  Perhaps this will provide the
	impetuous for EIA-422 (or is it 423?) to start appearing as
	standard equipment in personal computers, terminals, etc.
	Are there interface chips that can operate at this speed and
	take most of the load off of the CPU?  (DMA output and SILOed
	input.)

Casey