Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!agate!eris!chapman
From: chapman@eris (Brent Chapman)
Newsgroups: comp.dcom.modems
Subject: Re: MNP make for a faster modem?
Keywords: MNP
Message-ID: <6678@agate.BERKELEY.EDU>
Date: 24 Jan 88 03:00:26 GMT
References: <3027@killer.UUCP>
Sender: usenet@agate.BERKELEY.EDU
Reply-To: chapman@eris.UUCP (Brent Chapman)
Organization: UNIXversity of California at Berkeley
Lines: 31

In article <3027@killer.UUCP> tony@killer.UUCP (Tony Holden) writes:

>I've seen ads claiming that with the various MNP levels that the throughput
>on a 2400 baud modem is that of 9600 baud.  
>
>Is it hype or is it real?

It's hype.  MNP is an error detection and correction protocol.  A modem running
at 2400 baud with MNP will probably actually have slightly (_very_ slightly)
lower throughput than without MNP, because of the extra bits needed for the
protocol.  I happen to think it's worth it, though, because of the error
correction.

I spend lots of time dialed into various systems in Berkeley (which has _lousy_
line quality) using a USRobotics Courier 2400e MNP modem at home (I'm using it
now, as a matter of fact).  I always dial in at 2400 baud; sometimes I get an
MNP modem on the other end, and sometimes I don't.  I don't notice any
difference in speed when MNP is in use compared to when it isn't (and believe
me, I'd _notice_ a difference of 9600 vs. 2400 baud).  The only difference
is that occasionally when not using MNP, I get line garbage, and when using
MNP, output will pause for a half-second (while line garbage is detected and
corrected), then continue.


-Brent
--
Brent Chapman					Capital Market Technology, Inc.
Senior Programmer/Analyst			1995 University Ave., Suite 390
{lll-tis,ucbvax!cogsci}!capmkt!brent		Berkeley, CA  94704
capmkt!brent@{lll-tis.arpa,cogsci.berkeley.edu} Phone: 415/540-6400
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