Mike;
The USB option you are describing sounds like the best- if only - option for your particular dilemma!
If it's what I am thinking of, it would be a PCB mounted onto a riser, with the attachment Receptacles connected to a card slot fitting (like the knock-outs / removable plates on the back of an
AT type case, where Bus Adapters {"Cards"} poke out the back end, so cables can be connected and the adapter is useful
...).
The adapter interfaces the M/Board via ribbon cable, and typical pin conenctor.
If the option for USB / Serial bus interface is not available, I do believe there's several flavors of USB / IEEE 1394 "Firewire" setups on Bus Adapters / cards - ISA and PCI (maybe more in the PCI flavors, but who knows???).
I have a few books on the topic (USB), so let me know if you need a reference from the manual.
Scott35