Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!netcom!chris
From: chris@netcom.UUCP (Chris Lakewood)
Newsgroups: comp.dcom.modems
Subject: Re: High Speed transfers (was: Telebit registers)
Summary: Misinformation
Message-ID: <1358@netcom.UUCP>
Date: 2 Jun 89 19:16:10 GMT
References: <49@wells.UUCP> <1182@wpg.UUCP> <9858@dasys1.UUCP>
Reply-To: chris@netcom.UUCP (Chris Lakewood)
Organization: NetCom Services - Public Access Unix System (408) 997-9175 guest
Lines: 27

In article <9858@dasys1.UUCP> jpr@dasys1.UUCP (Jean-Pierre Radley) writes:
>CPU <-@19200-> TB <-@9600-> telephone lines <-@9600-> TB <-@19200-> CPU
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>Each computer talks with its trailblazer at 19200.
>Each trailblazer talks with the telephone line at 9600.
>The faster throughputs, up to 1700 or 1800 bytes/sec, occur on ASCII files,
>or data files with lots of blocks of nulls or spaces. The trailblazers can
>compress such files while in PEP mode.
>Files which are already compressed, or most binary files, will not transfer
>at such a rate.
>-- 
>Jean-Pierre Radley		CIS: 72160,1341		jpr@jpradley.UUCP

Wrong.  The two modems communicate using PEP at varying speeds up to
18,000 bps.  The content of the data (i.e. binary vs. ASCII) has
NOTHING to do with the speed at which the modems communicate.

An extension to PEP called PEP2 supports data compression and can
achieve speeds of 19,200 bps on compressible data.

It is not uncommon to see speeds of 1400 characters/sec or more on
data that is ALREADY compressed.  This is where Telebit is way ahead
of the other "high-speed" modem makers.  Their claims of 9600, 19200, or
38,400 are based on sending data which is highly compressible.  If the
data is already compressed, their thoughput goes WAY down.

Please check you facts.