>>The two cards are Adaptec ISA and a new Advansys PCI...
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>You can hang up to 7 devices on a single card. What Adaptec card, and what Advansys cards are you using? Neither of the devices is going to overburden even a 5MB/sec channel.
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>If the Adaptec card is working now, and there's an external SCSI connector on it, I'm sure that you'll have less trouble adding the necessary driver for the scanner to work in conjunction with the Adaptec than trying to get both cards in. Or if the Advansys has both internal and external connectors, and has ASPI support, I'd probably choose that, being a PCI card; SCSI CD-ROMs are supported generically though the ASPI driver, and if the card came with the HP scanner, there's no question of having support for the scanner.
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>Or pick up an Adaptec 29xx or the equivalent and scrap both cards - you could probably get away with the 2920, since neither device is bootable.

I guess the problems are these:

1) The scanner has a 50-pin SCSI cable, and the Adaptec external connector is 15 or so, way less (it's old)...I'm just guessing, but I don't think it's capable of handling the Scanner input even with an "adapter" cable...
2) The CD requires an internal connector (at least it has one now), and the new Advansys card is just a little teeny card with no internal connectors.

Maybe a new card would be best, except that this is only temporary for maybe 6 months until we have a higher-end machine available, which will probably have USB and resolve all this mess...

Well, thanks for the expertise on this matter, at least I'm aware of why things aren't working now :)