User`s guide

2-22
PowerDomain 2940UW/3940UW User’s Guide
PowerDomain 2940UW/3940UW User’s Guide
Stock Number: 510864-00, Rev. B Page: 2-22
Print Spec Number: 493742-00
Current Date: 2/20/96 ECN Date: 2/27/96
■ Any change in cable impedance, including the following
– A change in wire gauge from one cable to the next
– A change in the type of wire from one cable to the next
– A change in the type of insulation from one cable to the
next
– A change from twisted-pair to ribbon cables, which often
happens in drive cases
The effects of impedance changes will reduce the maximum
reliable length of the SCSI chain.
■ The maximum length of stub (drop) cables is 10 cm (4 in.),
and the minimum spacing between stub cables is 30 cm
(12 in.).
■ Flat single-ended cables should be spaced at least 0.05 in.
from the cable itself (when the cable is folded), from other
cables, and from any metallic part of the system.
Connecting Internal SCSI Devices
Note: If you are not installing internal SCSI devices, turn to
Connecting External SCSI Devices—Tower Models on
page 2-34 or Connecting External SCSI Devices—Desktop
Models on page 2-41.
Before installing an internal SCSI device, refer to the
documentation included with the device for installation
instructions. Sometimes a SCSI device must be installed
before you can connect it to the accelerator card.