SCSI Standards

Standard	Internal Interfaces Used	External Interfaces Used	Transfer Rate	No. Devices on Chain	Data Bus Bit Width	Maximum Cable Length
SCSI-1	50-pin	50-pin Centronics	5 MB/s	7	8	6m
SCSI-2	50-pin	50-pin Centronics	8 MB/s	7	8	6m
		25-pin LPT Type
Fast SCSI-2	50-pin	50-pin Centronics	10 MB/s	7	8	3m
		25-pin LPT Type
		50-pin HD
Wide SCSI-2	68-pin	68-pin HD	20 MB/s	15	16	3m
	80-pin SCA
Ultra SCSI-3	50-pin	50-pin Centronics	20 MB/s	7	8	1.5m (3m)
		50-pin HD
Ultra SCSI-3 HVD	50-pin	50-pin Centronics	20 MB/s	7	8	25m
		50-pin HD
Ultra-Wide SCSI-3	68-pin	68-pin HD	40 MB/s	15	16	3m
	80-pin SCA
Ultra-Wide SCSI-3 HVD	68-pin	68-pin HD	40 MB/s	15	16	25m
	80-pin SCA
Ultra2 SCSI LVD	50-pin	50-pin Centronics	40 MB/s	7	8	12m
		50-pin HD
Ultra2-Wide SCSI LVD	68-pin	68-pin HD	80 MB/s	15	16	12m
	80-pin SCA
Ultra160 LVD	68-pin	68-pin HD	160 MB/s	15	16	12m
	80-pin SCA
Ultra320 LVD	68-pin	68-pin VHDCI	320 MB/s	15	16	12m
	80-pin SCA

Notes


			Additional internal and external interfaces will be added as they are discovered for their appropriate standard. The Ultra SCSI-3 specification calls for a 3m cable with fewer than four devices. More than four devices requires a maximum length of just 1.5m.