Dell OptiPlex Gxi - Manual (Page 96)

7-10 Dell OptiPlex GXi Low-Profile Systems Reference and Installation Guide
• 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,
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.
Table 7-1. SCSI Termination Guidelines
Configuration
SCSI Host
Adapter Card Internal Narrow
SCSI Device(s) Internal Wide SCSI
Device(s) External SCSI
Device(s)
Internal narrow
and wide SCSI
devices Termination
enabled for upper
8 bits Termination
enabled for lower
8 bits on last device Termination
enabled for all
16 bits on last
device Not applicable
Internal wide
SCSI and external
narrow SCSI
devices Termination
enabled for upper
8 bits Not applicable Termination
enabled for all
16 bits on last
device Termination
enabled for lower
8 bits
Internal wide
SCSI and exter-
nal wide SCSI
devices Termination dis-
abled Not applicable Termination
enabled for all
16 bits on last
device Termination
enabled for all
16 bits
Internal narrow
SCSI and external
narrow SCSI
devices Termination dis-
abled Termination
enabled for lower
8 bits on last device Not applicable Termination
enabled for lower
8 bits
Internal narrow
SCSI devices only Termination
enabled for lower
8 bits Termination
enabled for lower
8 bits on last device Not applicable Not applicable
Internal wide
SCSI devices only Termination
enabled for lower
8 bits Not applicable Termination
enabled for all
16 bits on last
device Not applicable