Chapter 4: Understanding SCSI
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21
The following figure shows SCSI devices connected to the external connector.
Maximum Cable Lengths
The total length of cabling (internal and external) on the SCSI bus cannot exceed the
maximum lengths listed in the following table. The third column lists the maximum number
of SCSI devices you can connect to the SCSI card.
Terminated Device
Maximum Cable Length
Data Transfer Rate
Maximum Devices
Supported
25 m (82.0 ft)
Ultra320 SCSI (320 MB/sec)
Ultra160 SCSI (160 MB/sec)
Ultra2 SCSI (80 MB/sec)
1
12 m (39.4 ft)
Ultra320 SCSI (320 MB/sec)
1
Ultra160 SCSI (160 MB/sec)
Ultra2 SCSI (80 MB/sec)
1
Mixing Fast/Ultra devices with Ultra320/Ultra160 and Ultra2 SCSI devices causes the entire SCSI bus to default to
Ultra SCSI speeds and cable length requirements.
15
3 m (9.8 ft)
Fast Wide SCSI (20 MB/sec)
15
3 m (9.8 ft)
Fast SCSI (10 MB/sec)
7
3 m (9.8 ft)
Ultra SCSI (40 MB/sec for 16-bit, 20 MB/sec for
8-bit)
4
1.5 m (4.9 ft)
Ultra SCSI (40 MB/sec for 16-bit, 20 MB/sec for
8-bit)
5-7
2
2
Ultra SCSI data transfer rates do not currently support more than seven devices connected to the SCSI card due to
cable lengths.
