Path: utzoo!attcan!uunet!steinmetz!davidsen
From: davidsen@steinmetz.ge.com (William E. Davidsen Jr)
Newsgroups: comp.dcom.modems
Subject: Re: Are MNP modems noiser than non-MNP (also want rec. for some)
Keywords: MNP line noise want recommendations
Message-ID: <11535@steinmetz.ge.com>
Date: 15 Jul 88 13:39:52 GMT
References: <636@drexel.UUCP>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: General Electric CRD, Schenectady, NY
Lines: 38

In article <636@drexel.UUCP> jeff@drexel.UUCP (Jeff White) writes:

| 1. Are all MNP modes pretty inferior in performance and noise rejections when
|    operating in non-MNP mode, or was the one modem I worked on just a bad
|    example (a lemon)?

  No. I don't know if you have a bad brand or a bad example, but not all
modems with MNP have noise problems.

| 2. Any recommendations for 300/1200/2400 baud modems which are reasonably
|    priced and have MNP (or, can be upgraded to it at a later date at a 
|    reasonable cost)?

  We have hundreds of MultiTech 224E guys. All have MNP, most class
three, a few class five. We're still buying them, and have been very
happy. 

  There is a problem in calling a non-MNP modem if you don't turn off
the "auto-MNP" feature. When the modems have established carrier and
baudrate, the MNP (calling) modem will send a tone burst which means
"would you like to play MNP with me?" If the system you're calling has a
login sequence, such as UNIX (and most BBSs), this can mess up the login
sequence or cause a false baudrate. 

  The simple soultion to this is to run the line from the computer to
the modem at a fixed speed, like 4800, and let the modem do the flow
control. That's not always possible, I realize. 

  MNP does more for interactive use than for file transfer (I'm going to
hear about that one) because file transfer protocols will reject bad
packets while you can't reject a stream of bad characters on a screen,
or use a system when it's getting a bunch of noise characters.

  Hope this helps, I'm sure thatre will be other opinions.
-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me