Xref: utzoo comp.sys.att:8111 unix-pc.general:4177
Path: utzoo!attcan!uunet!portal!cup.portal.com!thad
From: thad@cup.portal.com (Thad P Floryan)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: 7300 and 9600 baud modems
Message-ID: <24424@cup.portal.com>
Date: 23 Nov 89 23:42:37 GMT
References: <3311@convex.UUCP>
Organization: The Portal System (TM)
Lines: 32

Dale Lancaster in <3311@convex.UUCP> laments the apparent slow data transfer
while evaluating a Microcom QX/12K modem at 9600 baud on his UNIXPC.

The "problem" (as it were) is the window driver for the UNIXPC and its s-l-o-w
screen writes.

The UNIXPC itself is more than capable of handling 19,200 baud over its
serial port(s).

Lenny Tropiano (and others) have Telebit modems which, in PEP mode, have been
reported by them as successfully and continuously achieving true data rates
in excess of 1100 bytes per second over the serial port.

I use Digicom 9624LE V.32 modems and also enjoy the same data rates, as I also
do with direct-connect serial-serial connections to other computers from the
UNIXPC.

The above transfer rates are for uucp (either e or g protocol) and, as I've
also verified, for zmodem.

Dale hinted he was using ``cu'' for his tests, and my recollection of cu's
docs is that cu artificially slows the data rates so you can read what's
appearing on the screen!  :-)

The combination of cu's throttling-back and the window manager's slowness
will produce the apparent slowness observed by Dale.

As a suggestion for modem evaluation, get a second modem and call into your
UNIXPC from a { system | terminal } which is known to meet your specs, and
THEN evaluate the throughput.  I believe you'll be pleasantly surprised.

Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]