Sounds like you have an HP. I have a Scanjet IIcx that came with that crappy-ass ISA card. Everytime I had to reinstall Windows, getting that thing to work was a pain.

Currently, I have a generic PCI SCSI card for the purpose of keeping that workhorse of a scanner. My freind Moe always has weird cables. This is likely the one you need. It's the one I have. Works like a charm.