From: ar4@sage.cc.purdue.edu (Piper Keairnes)
Newsgroups: comp.sys.mac.comm
Subject: Re: High speed modems... which to buy?
Date: 29 Sep 92 19:35:14 GMT
Distribution: na
Organization: Purdue University

pebi.717789487@sirocco.aem.umn.edu> pebi@aem.umn.edu (Peter A. Bidian) writes:

>ar4@sage.cc.purdue.edu (Piper Keairnes) writes:

>>The V.32, V.32bis, V.42bis descriptions in advertisments are not terribly
>>helpful in describing actual capability/compatibility. Could someone please
>>summarize the types of modems and modes available?

>Oh... I would be grateful for this piece of information too!

This is the best/only response I received... I thought it was very useful
and hopefully others will too. This response has been reposted without
permission from the original respondent.

---------------------------------------------------------------------------

Well here is a brief summary of hish speed modems:

V.32-This is a sync 9600 protocal...if it says V.32 is should be able to connect to any other V.32 modem at 9600.

V.32bis-This is a 14400 Scyn protocal...if it says V.32bis it can connect to 
V.32 modems at 9600 and V.32bis modems at 14400.

PEP-This is a telebit propritary 19200 protocal...it's only disadvantages are
it is expensive since you can only get it on Telebit modems and it does not
handle line noise well.

HST-This is a US Robotics Proprietary 16800 protocal and handles line noise much better than the Telebit.

Super PEP-This is what the world blazers use and I think it is 28800.  again it
does not handle line noise well.

Other numbers to notice:

V.42- this is the standard in error correction

V.42bis-this is a data compression standard that can increase throughput by
a factor of 4 on any modem.

MNP4-Another, older, error correction standard

MNP5-Another, older, compression standard that can increase throughput by a
factor of 2 with any modem.


My personal recomendation is to buy a V.32bis modem with V.42 and V.42bis.  This
is the standard today...it will connect at very good speeds to a telebit and
any other modem.  They are also cheep...you can get them for under $300 
compaired to over $1000 for a telebit for $500 for a US Robotics.  The other
thing that you will probably get for "free" with your modem is send recieve fax
wich is nice.  You MUST buy a hardware handshaking cable...you can get the modem to work without it but it will increse throughput by up to 50% for $8.

Brands that I have personally has good and bad experiences:

US Robotics...They are the best...the modems are indistuctable and they often
perform free upgrades to new standards IE when V.42 V.42bis came out they 
upgraded my modem for free.  They tend to be pricier, but they have the
Sportster line that is price competitive with other modems.

Practical Peripherals...again they are very good...they, like URS, have a long
warrentee and offer inexpensive V.32bis modems.

Zoom...Stay away...they are cheep in all senses of the word.  

Supra...Same they are cheep in all senses of the word.

Hayes...Pricy but they make good modems...thier Optima line are not too overpriced

Again I would swear by USR and PP, they have both been reliable modems...I have
had 10 of each running non stop for 2 years without problem.

Randall

-- 
Piper Keairnes - Computer Science   ** PUCC Consultant for money. **
INTERNET: ar4@sage.cc.purdue.edu    **   Mac programmer for fun.  **