Path: utzoo!attcan!uunet!zephyr.ens.tek.com!uw-beaver!mit-eddie!wuarchive!emory!att!att!watmath!maytag!xenitec!zswamp!root
From: root@zswamp.fidonet.org (Geoffrey Welsh)
Newsgroups: comp.dcom.modems
Subject: Re: Can we back up a sec?
Message-ID: <2234.2727A6FD@zswamp.fidonet.org>
Date: 25 Oct 90 18:07:43 GMT
Organization: Izot's Swamp BBS - Kitchener, Ontario
Lines: 49

In a message to All on Oct 24, George Robbins (grr@cbmvax.commodore.com ) 
wrote: 
 >Message-ID: <15363@cbmvax.commodore.com>

 >Mode    Files   Characters      Seconds C/Sec
 >PEP     21      5858185         4700    1246.4
 >V.32    59      14904357        19764   754.11

   Wonderful. Zackly what I needed.

 >Note that these numbers aren't too surprising, the 7500 char/sec
 >is about what you'd get one a direct connect at 9600 baud,

   Don't forget that the modems will have been using a synchronous framing 
technique (most likely MNP3 plus MNP4 for a couple of T2500s under V.32), 
which brings the 100% mark close to 1200 CPS (as opposed to 960 CPS for async 
framing over a 9600 bps null modem). If you take that into consideration, the 
750 CPS rating is disappointing.

 >Increasing window size or packet size, or changing protocols 

   I presume that you were using standard 64-byte packets; what window size 
were you using (7, 3, or 1)?

   Thanks for your reply!

 >help the V.32 get closer to 9600 BPS, but wouldn't do much 
 >for the the PEP
 >mode unless the protocol was adaptable to PEP packetizing 
 >charactersitics.

   Hmm, the 'e' protocol should work fine over a PEP modem *if* you are sure 
that your async connection to the TB is absolutely error-proof. It might even 
beat 'g' protocol spoofing performance...

 >Protocol experiments are difficult and don't neccesarily 
 >help the average guy with a binary license.

   Sad but all too true.
 
 

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