Computone ATvantage 8-port not found

[Scott McClure]

I am having great difficulty installing a Computone ATvantage 8-port
"smart" serial card on a 386/33 (Mylex motherboard) under SCO Xenix 2.3.3.
The driver installs without a hitch, but when I reboot the system, I get the
message "No Computone boards found."  I followed the manual and set it up
for IRQ15, which is unused on the system.  I even booted in DOS and checked
with debug, and it shows IRQ15 clear.  The rest of the system consists of
a 160Mb ESDI hdd, one 1.2Mb & one 1.44Mb fdd on an Ultrastor Ultra 12F 
controller, a Diamond SpeedStar VGA card, and 4Mb of RAM.  The Computone
has an 8088, and rev 3.17 ROM (latest version, or so I've been told), and
the driver is ver. 4.54.

Any ideas are welcome.

Thanks in advance!!

-- Scott