All SCSI devices should be backward compatible with older SCSI standards. Problem is that, AFAIK, UW-SCSI uses 64 pin and SCSI-2 uses 50 pin. You'll need an adaptor. But the protocol doesn't need converting.
My advice - get a cheap 2.5" IDE drive and an IDE->SCSI converter. It's cheaper and better than a SCSI one. Don't know if such a converter will fit with a 2.5" drive in an A1200 desktop case, though...
