Path: utzoo!attcan!uunet!zaphod.mps.ohio-state.edu!julius.cs.uiuc.edu!ux1.cso.uiuc.edu!news.cs.indiana.edu!maytag!xenitec!zswamp!root
From: root@zswamp.fidonet.org (Geoffrey Welsh)
Newsgroups: comp.dcom.modems
Subject: Re: 2400/MNP5 + CONNECT = 2400 baud?????
Message-ID: <4100.273E9D21@zswamp.fidonet.org>
Date: 12 Nov 90 05:25:10 GMT
Organization: Izot's Swamp BBS - Kitchener, Ontario
Lines: 41

Larry Snyder (larry@nstar.uucp ) wrote: 

 >Here in nstar we lock all the modems at 19200 baud and 
 >enable hardware
 >flow control.  Then the modems all handle the stepping down 
 >to 2400 and
 >1200 baud - but the DTE is always set to 19200.  This 
 >results in transfer
 >rates in excess of the carrier (if both ends are using MNP5) 
 >- plus
 >excellent transfer rates at high speed (1700cps on the HST, 
 >and 1400cps
 >on the Trailblazers)..

   This is fine & dandy, and in fact the person to whom I replied reported 
having tried this with unsatisfactory results. The problem is that software 
interrogating /dev/tty will probably be told that you're operating at 19,200 
bps. If and when a user logs on at 2400 (or 1200... or 300!) and asks to 
perform a download, you want the estimate of the download time to be based on 
the modem's connect speed, not your locked port speed.

   This is the beauty of the driver-internal speed locking: as far as the 
software is concerned, it's talking to the serial port at the modem's connect 
speed. All estimates were based on connect speed, and stty < /dev/tty 
(actually, its DOS equivalent) would report the CONNECT speed, not the physical 
communication speed.

   I don't have to tell you this; you must have encountered it a couple of 
years back (I was network echomail co-ordinator for southwestern Ontario in 
'88 and I remember a regional echo co-ordinator named Larry Snyder. I thought it 
was rather silly of anyone south of Canada to call their system the "Northern 
Star"... alas, I stray from the conference topic.
 

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