Grex Info Conference

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Grex Info Item 22: Connecting to Grex when you have a higher speed modem
Entered by srw on Sat Feb 13 17:33:51 UTC 1993:

I have had trouble connecting to Grex since I started about 6 weeks ago.
I attempt to connect via a 9600 baud modem (which goes down to 2400 when 
talking to Grex of course). After getting the 'Breakfast of Champions'
message, it goes haywire and thinks I'm on at a different baudrate.
I took STeve's advice and tried typing characters until I got its attention.
I was usually able to log in after a few minutes, but this was very
frustrating.

Now I have stumbled upon the solution (at least it worked beautifully the
first time I tried it). I got this info from the Hardware conference item #20,
but I'm sharing it here because I think more people who need it will be lookin
here. The solution is to suppress MNP protocol that is not supported by the
Grex 2400 baud modems. This is done by inserting \N0 in your dialout string. I
now will be using AT\N0TD7613000 . I hope this works for others of you out
there with higher speed modems.

10 responses total.

#1 of 10 by tsty on Sat Feb 13 18:10:30 1993:

darn, that is what I've been doing since I got this modem, at\n0 turns
off all "protocol auto-negotiation" and (if you escape back to command
mode) at\n3 or at\n2 restartess the autonegotiation.
  
Sorry I didn'T decipher that earlier .....hmmmmmmmm

#2 of 10 by remmers on Sun Feb 14 01:09:46 1993:

What brand of modem are you using?  Different high speed modems
have different commands for turning off protocol negotiaion.
Standardization seems lacking in this area.  With my modem,
a Practical Peripherals 9600SA, one uses AT&Q0.

#3 of 10 by mju on Sun Feb 14 04:27:49 1993:

The necessary command code varies, because there was never an official
Hayes standard for MNP commands.  Microcom was the first modem maker to
come out with MNP modems (makes sense, since MNP stands for Microcom
Network Protocol), so some vendors have copied the Microcom commands.
Supra is one, as well as other modem makers.  Other manufacturers, such
as ZyXEL and Telebit, have chosen to branch out into their own command
set; older Telebit modems use a combination of the S95, S96, S97, S98,
and S106 registers, while newer Telebit modems use S180, and ZyXEL
modems use &K.

#4 of 10 by srw on Sun Feb 14 07:30:25 1993:

Well, my modem is a "Magic" modem, packaged by MacProducts USA, a mail-order
company. I am sure there is an OEM manufacturer, but the comprehensive
manual calls it simply "faxmodem" throughout.

I saw the \N0 command in the Hardware conf. and checked it in this manual
where it shows this to be "Normal link only with buffering", as opposed to
\N1 Normal data link without buffereing
\N2 Reliable Link only, and
\N3 Auto-reliable link

It had not occurred to me that this might be non-standard, since the suggested
fix matched my manual and worked for me! Now that you mention it, it makes
sense though. I'm just grateful to have found out that there were "tickler"
characters being sent by my modem which were being utterly misinterpreted
and that these characters could be suppressed.

#5 of 10 by mju on Sun Feb 14 07:50:50 1993:

Yep.  The problem is that the MNP handshaking characters can look like a
BREAK to a non-MNP modem such as Grex's.  And when Grex sees a BREAK,
it assumes that it's a framing error due to mismatched baud rates, and
steps to the next baud rate.  If you get the login prompt at the wrong
speed, you can usually hit BREAK repeatedly until you get the correct
speed again.

#6 of 10 by tsty on Sun Feb 14 08:32:37 1993:

My modem, in ref to remmer's #2, is a Zoom V.42bis. And the 
speeed buffering is about the only advantage, except for 
possibly REALLY strong chracter recognition above line noise
taht everyone seems to have, except for "me and my Zoom-Arrow."

#7 of 10 by rlb on Wed Feb 17 07:13:35 1993:

I use an Image Twincom 144/DFi and have found the recommended 2400
initialization string to work quite well:
 
AT&Q6 S36=3 S48=128
 
The advantage of the &Q6 over &Q0 is that the DTE speed can differ from
the telco line speed, which is handy if you have your comm program set to
57600.  With &Q0 you may have noticed that your DET speed MUST match the
telco line speed.
 
S36=3 insures that the modem stays on line and a Normal mode connections
is established.
 
S48=128 disables the detection and negotiation phases; the modem proceeds
at once with the fallback action specified in S36 (default = 5), which is
to first attempt an MNP connection, and then fallback to a Normal connection.

I also have a PM9600SA and these settings work just as well with it.

Downloading at 14400 is twice as fast as the 9600 and one is quickly spoiled.
Now 9600 seems to be a bit pokey.

#8 of 10 by kain on Sat Mar 25 15:08:41 1995:

uh I'm kinda clueless here what should I do if I have a magnum fax modem 144?

#9 of 10 by kain on Sat Mar 25 15:24:16 1995:

I'm still conf. in the initilization string or what ever or in the dial prefix;
for me either way it says error.

#10 of 10 by srw on Sun Mar 26 19:42:56 1995:

What is your init string and your dial string?

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