Path: utzoo!utgpu!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!ists!stpl!bbm!aaron
From: aaron@bbm.UUCP (Aaron Burns)
Newsgroups: comp.unix.xenix
Subject: computone intelligent ca4rds
Keywords: computone intelligent signal level
Message-ID: <828@bbm.UUCP>
Date: 12 Jan 90 17:44:01 GMT
Reply-To: aaron@bbm.UUCP (Aaron Burns)
Organization: BBM Bureau of Measurement, Toronto
Lines: 45



About 3 months ago I came up with a cheap way to give interested parties
on other floors in our building a fast connection to our Xenix systems - 
Bell 'in-house data channels' (direct phone lines) coupled with short haul 
modem eliminators (SHM's, also line drivers).  Total connection cost $370 
(Canadian) plus $6.90/month for the line.  As these modems are self-powered 
in their most compact form, I called Computone to confirm that their cards could
power at least ten SHM's.  Computone's technical people said ok,
"you shouldn't have any problem".  

The first link went in between a Computone Intelliport AT-16 and a 
PC-AT with Kermit emulating a VT-100 on a 'standard' serial port, 
and is functioning properly at 19,200 between two floors.  The second 
link was set up later between a Computone Intelliport AT-8 (on a different
system with two such cards) and, again, a PC emulating a VT-100.  It didn't
work.

After much trial and tribulation (no-one ever suggested a power problem,
and every component tested good in isolation), we discovered that none
of the SHM's could do a loop-back while on the AT-8...but worked just
fine off a standard port and an AST 4-port dumb card.  The conclusion is 
insufficient juice to power the SHM's.  We backed this up by putting a 
longish (155 foot) cable between the two systems (ie between an AT-16 
and an AT-8).  While "Managing UUCP and Usenet" (O'Reilly and Associates)
states that a 9600 baud connection is feasible out to 250 feet, 
this cable (shielded, low-capacitance) kept losing dtr, and (with -clocal
in the gettydefs entry) garbled transmissions at 9600.  When the AT-16 end 
was hooked to an AST port, dtr became stable and data transmission 
was flawless.  It appears that the Computones just don't put out much
of a signal.  I don't have test equipment to directly confirm this.

I will call Computone today, but - how could they help?  After all, the cards
work OK with just terminals, and that is what they're advertised for.  If
they do say anything usefull, I'll let you know.  Anyone with similar
experiences - please tell us!
 

 
-- 
Aaron 'crash and' Burns      "Nothing I say on the net is binding
Metro Works                   to our corporation"
Toronto, Ontario             "Life is a forge, and the purest metal
(416)392-4310                 comes from the hottest fire"
aaron@bbm.UUCP               ...utzoo!yunexus!stpl!bbm!aaron