Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!cs.utexas.edu!usc!apple!metaphor!xymox!philf
From: philf@xymox.metaphor.com (Phil Fernandez)
Newsgroups: comp.dcom.modems
Subject: Re: Microcom Modems.....Are they any good?
Message-ID: <906@metaphor.Metaphor.COM>
Date: 7 Dec 89 07:11:01 GMT
References: <89Nov30.204838est.58891@ugw.utcs.utoronto.ca> <2601@ucsfcca.ucsf.edu>
Sender: news@metaphor.Metaphor.COM
Reply-To: philf@xymox.metaphor.com (Phil Fernandez)
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 43

In article <2601@ucsfcca.ucsf.edu> jst@cca.ucsf.edu.UUCP (Joe Stong) writes:
>In article <89Nov30.204838est.58891@ugw.utcs.utoronto.ca>
>	CS117341@YUSol.BITNET (Norman) writes:
>
>>Oh, on a (slightly) related note, I've noticed that when connecting
>>to non-MNP modems with MNP enabled on the T2500 results in an
>>unusable connection.  Maybe I'm mistaken, but I thought MNP was
>>supposed to be a transparent protocol negotiated by both modems
>>after they connect.  Does anyone have any suggestions?
>
>It was also my understanding that MNP was supposed to have invisible
>negotiations.  I had a certain amount of grief with an MNP modem calling
>a non-mnp modem, where the device attached to the non-mnp modem would
>print an error message and hang up if it didn't get a correctly typed
>password directly after connecting.  What it was receiving was something
>like (octal) 377 375 after CD came up.  I had to turn off the 
>auto-reliable mode (MNP) to prevent this from happening.

From the _Telebit T2500 Reference Manual_, in the documentation for the
S95 parameter (MNP Operating Mode):

   ...  In addition, if the answer modem does not support MNP, it
   will receive a burst of characters from the originating modem
   during the first 4 seconds of the call as the originating modem
   attempts to make an MNP connection.

Indeed, this burst of characters sent by my 2500 munges most every
non-MNP modem that I ever dial.  I've resorted to configuring the 2500
with S95=0 (MNP disabled) in its NVRAM.  Then, I use "ATS95=2DT...."
as my dialing mode when calling presumed-MNP modems.

Of course, this effectively defeats the entire "Auto-reliable Mode"
feature (S95=2), but c'est la vie.

pmf


+-----------------------------+----------------------------------------------+
| Phil Fernandez              |             philf@metaphor.com               |
|                             |     ...!{apple|decwrl}!metaphor!philf        |
| Metaphor Computer Systems   |"Does the body rule the mind, or does the mind|
| Mountain View, CA           | rule the body?  I dunno..." - Morrissey      |
+-----------------------------+----------------------------------------------+