Connecting External Options
The following table shows the maximum cable lengths for
connecting SCSI devices, based on data-transmission rates.
Note: The maximum cable length for an external cable is
determined by subtracting the length of the internal cable
being used from the maximum length of SCSI cable that can
be used based on the speed of the data transfer.
Table 2. Maximum External SCSI Cable Lengths
5 MB Per Second or Slower Data Transmission Rates
Note: Maximum cable length − internal cable length = external cable length.
Maximum Length of SCSI cable = 6 meters (19.7 ft.)
Length of SCSI narrow cable = 1 meter (3.3 ft.)
Length of SCSI Fast/Wide cable = 1.5 meters (4.9 ft.)
When a narrow internal cable is used, the maximum length of the SCSI
external cable = 5 meters (16.4 ft.)
6 meters − 1 meter = 5 meters, or
19.7 ft. − 3.3 ft. = 16.4 ft.
When a Fast/Wide internal cable is used, the maximum length of the SCSI
external cable = 4.5 meters (14.8 ft.)
6 meters − 1.5 meters = 4.5 meters, or
19.7 ft. − 4.9 ft. = 14.8 ft.
Greater Than 5 MB Per Second Data Transmission Rate
Note: Maximum cable length − internal cable length = external cable length.
Maximum Length of SCSI cable = 3 meters (9.8 ft.)
Length of SCSI narrow cable = 1 meter (3.3 ft.)
Length of SCSI Fast/Wide cable = 1.5 meters (4.9 ft.)
When a narrow internal cable is used, the maximum length of the SCSI
external cable = 2 meters (6.5 ft.)
3 meters − 1 meter = 2 meters, or
9.8 ft. − 3.3 ft. = 6.5 ft.
When a Fast/Wide internal cable is used, the maximum length of the SCSI
external cable = 1.5 meters (4.9 ft.)
3 meters − 1.5 meters = 1.5 meters, or
9.8 ft. − 4.9 ft. = 4.9 ft.
Chapter 5. Installing Options 273
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