Requirement - Do not attach any external SCSI devices to the onboard SCSI connector of the I/O+ board in card cage slot 1.
To add external SCSI devices, use the SBus slots on the I/O+ board, or add a second I/O+ board. You may use either an SBus+ I/O board or a Graphics+ I/O board.
Maximum - The maximum length for a chain of single-ended (non-differential) SCSI cables is 6.0 meters (20 feet).
Maximum - The maximum length for a chain of differential SCSI cables is 25 meters (82 feet).