Path: utzoo!utgpu!watserv1!maytag!xenitec!zswamp!root
From: root@zswamp.fidonet.org (Geoffrey Welsh)
Newsgroups: comp.dcom.modems
Subject: 2400/MNP5 + CONNECT = 2400 baud?????
Message-ID: <3780.273A463B@zswamp.fidonet.org>
Date: Thu, 08 Nov 90 14:39:06 EDT
Organization: Izot's Swamp BBS - Kitchener, Ontario

Gray Watson (cgwst@unix.cis.pitt.edu ) wrote: 

 >Now the problem: users logging into my system at *normal* 
 >2400 baud (1200 and
 >300 also) have their environment set to 9600 baud.  The 
 >modem handles the
 >speed mismatch so there is not a problem there, but anything 
 >that uses
 >a termcap-like database (gnu-emacs for example) thinks you 
 >are on a 9600 baud
 >line and sends 4 times the number of padding NULLs.

   FidoNet type folk have solved this problem rather neatly: the serial drivers 
we use support a 'locked' mode; that is, the driver will always communicate with 
the modem at a fixed speed (9600, 19200, 38400, whatever) regardless of what the 
application sets the speed to.

   In this way, a modem may report "CONNECT 2400/ARQ" (example: USRobotics 
Courier models w/MNP) and all software down the line knows that the connect is 
over a physical 2400 bps carrier, but the driver will continue to talk to the 
modem at the higher fixed rate. In this way, efficiencies of over 100% are 
sometimes reported... we *love* to see such reports. <grin>

   This, of course, would require an extensive patch to the serial drivers... 
they'd have to remember what baud rate they're logically operating at so that 
they can report it when queried, but the actual communication speed must be set 
separately and not be overridden by standard calls...

 >I have tried to set my modems to auto-baud on the Sparc 
 >serial connection
 >in parallel with the modem connection but I am finding that 
 >MNP5 connections
 >get set to 2400 baud.  Back where I started with no speed 
 >increase.

   Some modems (e.g. "ATI 2400etc" models) have a three-line connect report:

CARRIER 2400
PROTOCOL: MNP
CONNECT 9600

   This, however, leaves you with your original problem. The partial benefit is 
that, for non-MNP callers, the CONNECT string reports 2400, not 9600.
 

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