User`s guide

Appendix B SCSI Configuration Guide
SCSI Termination
Quantum DAT 160 User’s Guide 57
• On external Quantum drives, the ID is displayed on the rear panel
and can be set by pressing the little buttons above and below the
number (using a ball point pen) (see Check the Drive’s SCSI ID
on
page 28).
• On removable Quantum drives, the ID is set on the back of the tape
array (see Check the Drive’s SCSI ID
on page 28).
SCSI Termination 2
Terminators are essential, as they provide the correct voltages on the SCSI
bus and prevent unwanted signal reflections from interfering with data
transfers. The rule is:
• There must be termination at both physical ends of the bus and only
at the ends.
There are two main types of termination, active and passive. Active
terminators reduce interference and allow faster data through
Quantumut. On devices with high transfer speeds, such as Quantum
DAT devices, active termination is required, using an LVD or multimode
active terminator. (Multimode terminators allow both LVD and single-
ended devices to be connected to the same bus. They detect the type of
bus and automatically supply the correct termination. The terminator
supplied with Quantum DAT tape drives is LVD. Multimode terminators
may be used instead.)
Normally the HBA forms one end of the SCSI bus and provides
termination. You only need to ensure that the other end of the bus is
terminated.
Internal Drives 2 A suitably terminated LVD internal ribbon cable is supplied with the tape
drive. The terminator is usually a small, rectangular block of plastic
attached to the cable end and marked ‘SCSI Terminator’.