Path: utzoo!mnetor!uunet!cbmvax!grr
From: grr@cbmvax.UUCP (George Robbins)
Newsgroups: comp.sys.amiga
Subject: Re: 19.2k baud modems
Message-ID: <3071@cbmvax.UUCP>
Date: 3 Jan 88 10:25:59 GMT
References: <7403@ccicpg.UUCP> <503@cord.UUCP> <4310@garfield.UUCP> <1329@sugar.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Distribution: na
Organization: Commodore Technology, West Chester, PA
Lines: 28

In article <1329@sugar.UUCP> peter@sugar.UUCP (Peter da Silva) writes:
> In article <4310@garfield.UUCP>, john13@garfield.UUCP (John Russell) writes:
> > I have heard figures of 100K bits/second for modems using this technique, but
> > I was under the impression you needed the same model on the other end due to
> > the specialized encoding used. Maybe like you say the Trailblazer will become
> > the standard.
> 
> And I was under the impression that Shannon's Theorem said that the hard limit
> for a voice line was 50K bits/second. I could be wrong (been known to happen,
> just ask anyone here), but I believe the person who told me this. He's a jerk,
> but a knowledgable one.

Shannon had to assume that the data was random.  If the data has patterns
that compression or other algorithms can take advantage of, then you can
obtain higher equivalent "bit rates", however you can probably argue that the
actual amount of theoretical "information" being transmitted is still less
than Shannon's limits.

Practically, the USR type 9600 baud or Trailblazer type modems may offer
you considerable cost savings if you transfer a lot of data, or the pleasure
of "direct connect" data rates even though you're dialed into your sites
host computer.  The tradeoff is currently between maximum data rate and
interactive turn-around/echo time, but both sides are still fighting hard.

-- 
George Robbins - now working for,	uucp: {uunet|ihnp4|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)