Connecting to external interfaces
Issue 3.3 February 2003 43
UltraSCSI connections
The following figure shows how to connect UniPack SCSI disk drives and tape drives to an
UltraSCSI card. A 68-to-68-pin VHDCI SCSI cable connects from the UltraSCSI PCI card
on the back of the computer to the IN connector on the back of the SCSI device that is
closest to the computer. A 68-to-68 pin SCSI cable connects from the OUT connector of
that device to the IN connector of the next device. Continue this process until all assigned
devices are connected in the SCSI chain.
When connecting SCSI devices, the last device in the chain MUST be terminated, either
via an auto-terminated device or with a manual terminator.
When using an auto-terminated SCSI device, you do not need to connect a SCSI
terminator to the OUT connector of the last SCSI device in the chain. T o verif y tha t the las t
device is auto-terminated, check the LEDs labeled Auto Ter m High and Auto Term Low on
the back panel of the device. In a CMS configuration, both LEDs are lit on the last device in
the SCSI chain. If a device in the SCSI chain is not the last device, neither termination LED
is lit.
When using a manually-terminated device, you must connect a SCSI terminator to the
OUT connector of the last SCSI device in the chain. When you connect the SCSI
terminator to the OUT connector, the LED on the terminator is lit.
68-to-68 pin VHDCI cable
Stackof three
external SCSI devices
Dual-channel
UltraSCSI card in PCI slot 2
IN
IN
IN
OUT
OUT
OUT
68-to-68 pin SCSI cable
Target
address
switch
Back panelof Ultra 5
scsiuni.cdr
(left) (right)