Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!emperor!brucek
From: brucek@emperor.scs.com (Bruce Klein)
Newsgroups: comp.dcom.modems
Subject: Over 1000 cps with PEP?
Message-ID: <1991Jun19.003439.7587@emperor.scs.com>
Date: 19 Jun 91 00:34:39 GMT
Organization: Mentor Graphics IC Group, San Jose, CA
Lines: 29

How are you people achieving this?

I have a number of Telebit modems here.  For this experiment, I called
a T2500 with a T1000 using the PEP protocol.  The modems were connected
to their hosts through 9600 baud serial ports.  

Using xmodem and the telebit xmodem support (s111=20) I was able to achieve
500 cps.

Next I tried zmodem.  With a Sun on one end and a Mac Plus running Zterm
on the other (same two modems) I was able to achieve peak thruput of 700
cps.  I was unable to sustain this though, and on average it delivered
about 400 cps.  There may be something wrong with my sz binary--on EVERY
file it produces a CRC error at bytes 6144, 13312, 20480, 27648, ....
(Anyone have any ideas about that?)

Are these figures reasonable?  If not, what could be the problem?  The
two phone lines in this instance were part of the same Centrex system,
and thus should be of good quality.  

Help!  




-- 
   Bruce Klein
   brucek@emperor.sjc.mentorg.com
   ... uunet!emperor!brucek