Apple PowerBook (Duo 270C) - Manual (Page 274)

Checking that the SCSI chain is properly terminated
To ensure accurate transmission of information, a chain of SCSI
devices must have a terminator at each end. Terminators are
built into some SCSI devices and can also be added externally.
n
The Duo Dock and the Duo MiniDock both have built-in
terminators.
n
External SCSI devices from Apple do not have built-in
terminators.
n
External SCSI devices from other vendors may have built-in
terminators; see the documentation that came with the
device.
What these facts mean to you: You do not need to add a
terminator at the beginning of the chain. You need to make sure
that the last (and only the last) device in the chain has an internal
or an external terminator.
If you are attaching one SCSI device
Make sure that there is
n
an internal terminator in that device, or
n
an external terminator attached to that device.
If you are attaching more than one SCSI device
Make sure that there is
n
an internal terminator in, or an external terminator attached
to, the last device; and
n
no other terminator (internal or external) in the chain.
If you have too many devices with internal terminators, your
Apple-authorized service provider can remove extra terminators.
Correct chain configurations are shown in the illustration on the
following page.
SCSI terminator
258 Chapter 13: Building a PowerBook Duo System