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From: UH2@psuvm.psu.edu (Lee Sailer)
Newsgroups: comp.sys.amiga
Subject: Re: Modems
Message-ID: <90256.111652UH2@psuvm.psu.edu>
Date: 13 Sep 90 15:16:52 GMT
References: <826.26EF2259@weyr.FIDONET.ORG>
Organization: Penn State University
Lines: 28

In article <826.26EF2259@weyr.FIDONET.ORG>,
Vince.Cleniuk@f70.n140.z1.FIDONET.ORG (Vince Cleniuk) says:
>
>Pardon, but what exactly is an MNP modem... are there advantages from
>using them over the 'regular' type of modem?
>
>Vince
>

When your computer gives the modem a packet of bytes to send, there are
two choices, 1) send the bytes as is, or 2) compress the bytes and add
error checking and error correcting bits.  In case 1, if some problem
occurs on route it is up to the sending and receiving computers to
realize that an error has occurred, and arrange to retransmit the packet
of bytes.  In case 2, the modems themselves can recognize that an error
occurred and often times repair it without bothering the computers at all.

Of course, there are many many compression and error correction methods.
MNP is one of them.

The main practical advantage of MNP is that, because of the compression,
transmission rates can be higher.  If you can pack 100 bytes of text
into 50 bytes of binary gibberish, and then unpack them at the other
end, then your 1200 bps modem will seem to run at 2400 bps.

It occurs to me.  Does this mean that little will be gained for the
transmission of ZOO and LZ files, since they are already compressed?
(assuming error free lines, of course)