I've never had option to fiddle with one of these things, so I might be a little foggy. If this the 2-way ethernet/modem put out by 3com, then there is hope of getting it set-up. The problem is going to be getting the carbus driver to recognize and load the proper modules for it, and then hopefully they'll bind it to the hardware. Since you have interrupts and an output in /proc/pci doesn't mean that pcmcia services saw it.
This may sound silly, but when you insert the card does the notebook do the 2 equal beeps, or 1 loud beep and a dull bonk tone?
Second, what's the output from lspci and lsmod. Also, what is the output from /var/lib/pcmcia/stab (this varies per system, so you might have to poke around) In that file is what Cardmgr sees and tries to bind with info from /etc/pcmcia/config.opts.
Lastly, what's the distro as there is some funkiness after kernel 2.4.5 when they started migrating nearly everything to in-kernel pcmcia. Luckily a few distros are still using pcmcia-cs as it works with nearly everything.