Xref: utzoo news.newusers.questions:2726 comp.dcom.modems:6670
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: news.newusers.questions,comp.dcom.modems
Subject: Re: Modem Speed
Message-ID: <2495@crdos1.crd.ge.COM>
Date: 6 Sep 90 19:18:47 GMT
References: <1664@gvgpvd.GVG.TEK.COM> <1990Aug30.023220.8554@ncsuvx.ncsu.edu> <659@texas.dk> <1990Sep4.150259.12379@savant.uucp> <887@stsim.ocs.com>
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Followup-To: news.newusers.questions
Organization: GE Corp R&D Center, Schenectady NY
Lines: 26


  There are currently three major players in the 9600 and up modem
protocol game. The standard is V.32, but it's not as widely used as the
others. If you are buying modeems for both ends you don't care.

  PEP protocol (Trailblazer) offers higher throughput than the line
speed for some protocols, notably uucp and (I believe) xmodem and
kermit. The packet envelope is stripped at the sending end and
reconstructed at the other end. Only the data flows, and throughput can
be 20-40% faster.

  The standard used by many ham radio and CP/M systems is (the HST US
Robotics). I'm not sure what this buys you other than compatibility.
That's not saying something bad, I just don't have a lot of time on
these modems.

  V.42 is a data compression scheme, and it may be effected by the
recent UNISYS patent on data compression. The last word I heard was that
software compression would be ignored, hardware compression (like a
modem) would be licensed.

  If I were buying modems I'd go Telebit T2500, with PEP and V.32.

-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
    VMS is a text-only adventure game. If you win you can use unix.