LSI Ultra160, User Manual

Page: 24 / 54

2-8 Detailed Host Adapter Installation
Figure 2.6 Multiple External SCSI Devices Chained Together
2.3 Terminating the SCSI Bus
The devices making up the SCSI bus are connected serially (chained
together) with SCSI cables. The first and last physical SCSI devices
connected on the ends of the SCSI bus must have their terminators
active. All other SCSI devices on the bus must have their terminators
removed or disabled. Refer to the peripheral manufacturer’s instructions
and to the user’s manual for your computer for information on how to
identify the terminator setting of each device and how to change it.
To utilize Ultra160 SCSI performance, you must only have LVD devices
on the bus. Do not mix any SE devices with LVD devices or the entire
bus will drop to SE speed, limiting bus performance to Ultra SCSI. LVD
peripheral devices are normally terminated with external terminators, but
are sometimes set with jumpers or with a switch on the peripheral.
Last Device
on Chain–
Termination
Enabled
These Devices Do Not
End Chain–
Termination
Disabled
Host Adapter
External Board Connector–
Plugging in automatically
enables termination