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From: CS117341@YUSol.BITNET (Norman)
Newsgroups: comp.dcom.modems
Subject: the "Transparency" of MNP...
Message-ID: <89Dec4.212759est.57389@ugw.utcs.utoronto.ca>
Date: 5 Dec 89 01:30:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 42

Hello all,

In a previous posting, I mentioned that MNP didn't seem to be very
transparent...

I received the following message from Bjorn Sjoholm:

>>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?

>       I have the same problem using Microcom AX/2424c Modems which
>       are MNP class 5. After days of struggling with the problem
>       I noticed, in the manual entry
>       for "AT\N", that when operating in "AT\N3"-mode (auto-reliable)
>       the modem needs 12 seconds (!) to drop down to normal mode!
>       The solution is to always use "AT\N0"-mode when calling
>       non-MNP modems.
>
>       Hope this helps,
>
>                       Bjorn

I checked the T2500 manual, and when you set S95=2 (auto-reliable), the modem
will attempt to connect with MNP for 4 second.  If it cannot negotiate MNP
within that time, it will fall back to non-reliable mode.

Unfortunately, when I try this, the modem does indeed take about 4 seconds
to show a CONNECT, however, at this point the modem doesn't seem to respond
to anything typed from the keyboard.  After 20 to 30 seconds, the connection
is dropped.

I suppose the only solution is to turn off MNP when you know the modem
on the other end is non-MNP.

*sigh*

Norman
cs117341@yusol.Bitnet                    cs117341@sol.YorkU.CA
cs117341%yusol@mivma.mit.edu             cs117341%yusol@cunyvm.cuny.edu