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From: tnixon@hayes.uucp (Toby Nixon)
Newsgroups: comp.dcom.modems
Subject: Re: Are there modems that can do V.29 and V.32? + other questions.
Message-ID: <1614@hayes.uucp>
Date: 1 Oct 90 11:27:47 GMT
References: <13159@june.cs.washington.edu>
Organization: Hayes Microcomputer Products, Norcross, GA
Lines: 45

In article <13159@june.cs.washington.edu>,
robertb@june.cs.washington.edu (Robert Bedichek) writes: 

> I am thinking of buying a T2500, however one site that I call is
> planning on getting V.29 9600 baud modems.  I understand that the
> T2500 does PEP and V.32.  I was kind of hoping that V.29 was a subset
> of V.32.  If this isn't the case, are there modems that can do both?

V.29 is NOT a subset of V.32.  V.32 can do full-duplex 9600bps on 
two-wire dial-up phone lines.  V.29 is designed for full-duplex only 
on four-wire leased lines, although it can do half-duplex on dialup 
lines (it is the 7200/9600 modulation scheme used for Group 3 fax, 
for example).  

V.29 is rarely used in PC-class modems.  Only Microcom MNP6 modems 
use V.29 modulation, but it is "hidden" as a fast-turnaround 
ping-pong modulation for error-control (it's not directly accessible 
to a synchornous host).  There are several companies that sell V.29 
modems for dial-up and leased lines for synchronous mainframe links, 
but I don't know of any that have both V.29 and V.32 in the same 
modem.

> The CS department here is thinking of buying a bank of V.29 modems.  Is
> it reasonable for us to buy a bank of V.29, but not V.32 modems?  Or
> should I go try to convince the administrators that V.29 + PEP, or V.32
> is almost as inexpensive?

Whether to buy V.29 or V.32 depends on the application.  If you're 
going to be using the modems for PCs or terminals calling in for 
interactive work, V.29 modems are NOT the way to go.  You can't 
generally get V.29 and other PC modulation schemes in the same modem 
(although some sites WANT to restrict access to only particular 
types of modems as a security measure).  V.32 modems are much more 
widely available, are much better for virtually all applications, 
and are soon going to be cheaper than V.29 because of higher volume. 
You can't get V.29+PEP in the same modem, as far as I know.

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