Table 7-1. Scsi Termination Guidelines - Dell OptiPlex GXi Reference And Installation Manual

•
If you are installing an internal wide SCSI device
(such as a wide SCSI hard-disk drive), you have a
68-pin internal SCSI cable as shown in Figure 7-14.
One end of this cable attaches to the wide SCSI
device and the other end attaches to the wide SCSI
connector on your SCSI host adapter card.
•
If you are installing an external SCSI device, you
have a shielded external cable that connects to the
external SCSI connector on the SCSI host adapter
card. You have a separate power cable to connect the
SCSI device to an AC power source.
Before installing SCSI devices in your computer, you must
configure the termination on your SCSI device(s) to con-
form to the guidelines shown in Table 7-1. In Table 7-1,
Configuration
Internal narrow
and wide SCSI
devices
Internal wide
SCSI and external
narrow SCSI
devices
Internal wide
SCSI and exter-
nal wide SCSI
devices
Internal narrow
SCSI and external
narrow SCSI
devices
Internal narrow
SCSI devices only
Internal wide
SCSI devices only
7-10 Dell OptiPlex GX i Low-Profile Systems Reference and Installation Guide

Table 7-1. SCSI Termination Guidelines

SCSI Host
Adapter Card
Termination
enabled for upper
8 bits
Termination
enabled for upper
8 bits
Termination dis-
abled
Termination dis-
abled
Termination
enabled for lower
8 bits
Termination
enabled for lower
8 bits
the term "last device" refers to the device attached to the
end connector on the corresponding SCSI cable. For
instructions on enabling and disabling termination, see the
documentation for your SCSI host adapter card.
CAUTION: Do not connect devices to all three
connectors (internal narrow connector, internal
wide connector, and external connector) on a single
SCSI host adapter card. Such a configuration is a
violation of the SCSI specification. You can safely
connect devices to any two of these three connectors
on a single SCSI host adapter card.
Internal Narrow
SCSI Device(s)
Termination
enabled for lower
8 bits on last device
Not applicable
Not applicable
Termination
enabled for lower
8 bits on last device
Termination
enabled for lower
8 bits on last device
Not applicable
Internal Wide SCSI
Device(s)
Termination
enabled for all
16 bits on last
device
Termination
enabled for all
16 bits on last
device
Termination
enabled for all
16 bits on last
device
Not applicable
Not applicable
Termination
enabled for all
16 bits on last
device
External SCSI
Device(s)
Not applicable
Termination
enabled for lower
8 bits
Termination
enabled for all
16 bits
Termination
enabled for lower
8 bits
Not applicable
Not applicable