- Maximum cable length for single ended slow SCSI is 6 meters. - For fast SCSI, it should probably be half that -- 3 meters. - For Ultra, cut it in half again -- 1.5 meters. Keep in mind that this is maximum allowable cable length, and that includes everything within a drive enclosure or CPU that shares the same SCSI chain. You can figure about 6" +/- worth of cabling internal to any drive enclosure.Using active termination, especially with Fast or Ultra is the most reliable way to go.