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From: fenger@galaxy.cps.msu.edu (Steven V Fenger)
Newsgroups: comp.sys.ibm.pc
Subject: Re: INFO needed about 9600 modems
Message-ID: <1991Apr19.235618.21334@msuinfo.cl.msu.edu>
Date: 19 Apr 91 23:56:18 GMT
References: <1991Apr19.141045.113@gnv.ifas.ufl.edu>
Sender: news@msuinfo.cl.msu.edu
Organization: Michigan State University, Computer Science Department
Lines: 58

In article <1991Apr19.141045.113@gnv.ifas.ufl.edu> sjs@gnv.ifas.ufl.edu writes:
>From: bjahn@wam.umd.edu (Guess ???     ),
>University of Maryland at College Park
>
>>I am wondering about the various 9600 modems. Escpecially the US Robotic
>>modems. What is the difference between the USR v.32 modems and the HST modems?
>>In general, what is the standard in 9600 modems, and is there much difference
>>in int/ext modems beside personal preference?
>>        What is difference between v32, v32.bis, v42, v42.bis and MNP5?
>>What would be a good buy for a modem that won't be outdated or will be off
>>standard in the future?
>>        Thanks in advance!
>
>
>All I know (others will have to fill in the blanks):
>
>V.21:     CCITT standard for 300 bps modems.
>V.22:     CCITT standard for 1200 bps modems.
>V.22 bis: CCITT standard for 2400 bps modems.
>V.32:     CCITT standard for 9600 bps modems.

V32.bis:  CCITT standard for 14.4Kbps.  I'm not sure this is truely an
          official standard yet.
V42:      CCITT standard for error correction.  Includes LAP-M and
          fallback to MNP1-4.
V42:      CCITT standard for on-the-fly data compression.  Smarter than
          MNP5, it doesn't try to compress already compressed data.

>MNPx:	  MNP = Microcom Networking Protocol, a modem error-correction
>          protocol.

Modem manufactures must license MNP standards from Microcom in order to
use them.  MNP1-4 is reasonable and is almost public domain.  MNP5 is
more expensive.  MNP7 & 9 is outragously priced so V42bis will dominate.

>CCITT:  Consultative Committee International Telegraph and Telephone.
>        An organization established by the United Nations to develop
>        worldwide standards for communications technology.

A US Robitic's HST modem is a 14.4Kbps/450bps async channel modem and is
not compatible with V32.  V32 does 9600bps in both directions.
US R. does offer the "DualStandard" which has both HST & V32 compatability.

What won't become obsolete?  At this point the only thing I can
see that is obsolete is V32 modems.  V32bis is coming out real soon.  Of
course, V32bis will cost more than V32 and a V32 modem can connect to a
V32bis modem.

As to HST vs V32 it depends on who you call.  Most IBM-related BBSes use
HST modems because sysops can get a great deal on one.  V32(bis) is a
world-wide standard, though, and for all types of computers.  The unix
world generally use Trailblazer modems with PEP standard (an async
channel modem like the HST.)

Steven Fenger
fenger@frith.egr.msu.edu  \
fenger@cps.msu.edu         >  But all roads lead to fenger@galaxy.cps.msu.edu
fenger@power1.ee.msu.edu  /