There are a lot of different SCSI connector types that have emerged over time:
I don't know what model SprintScan you have, but the SprintScan 45i I know has a 50-pin Centronics port ("C50", "Low-density 50-pin" and other names) and a 25-pin DB-25 port.
Given that your Adaptec 2930 SCSI controller has a 50-pin high density ("HD50") port, you will need either a 50-pin high density to 50-pin Centronics cable (like this
), or a 50-pin high density to 25-pin DB-25 cable (like this
Remember that the SCSI bus needs to be terminated on both ends, so you may also need a terminator, either with a Centronics plug (like this
) or with a DB-25 plug (like this