On Thu, 16 Feb 2012 16:22:34 +0000, John Rumm wrote:
What make and model of scanner, and which Adaptec card?

Yes, I think we need to know that first... I've seen all manner of
different Adaptec boards and SCSI scanners over the years, and trying to
determine cabling / termination / SCSI BIOS options is perhaps a bit
pointless without knowing the OP's actual hardware.

Broadly-speaking though, you need termination *once only* at *both* ends
of the SCSI bus, whether that be done via external terminators (either
active or passive) or by the scanner and Adaptec card (or some
combination thereof). The scanner's likely a narrow SCSI device; if the
Adaptec card is a wide adapter then care needs to be taken to ensure that
the high-side of the wide bus is terminated. Something also needs to
supply termination power to the bus - the Adaptec card can almost
certainly do it, and the scanner may be able to as well. The scanner
needs to be set to a different SCSI device ID than the Adaptec card.

I havve a few cables to work with, and something (double ended)
labelled as a passive terminator

Is it labeled as SCSI or has the SCSI logo on it? If not, I suspect
that's not SCSI, and plugging it into a SCSI bus might be a bad idea.

Depending on what connectors it has though, there's a chance that it's
wide SCSI on one side passing through to narrow SCSI on the other, while
terminating the high-side of the wide bus - but I don't recall ever
seeing a passive terminator for wide SCSI, only active ones.

cheers

Jules