Compaq Deskpro ap230 Hardware Reference Manual page 50

Every SCSI chain or circuit must be terminated (closed) at both


ends. Termination can be accomplished by using the terminating


feature on the device or by using a terminated cable.
Some devices may not have terminating jumpers on the device.
Termination on these devices must be achieved with terminated
cable.
Turn on an external SCSI device before turning on power to the
computer. This enables the system board controller to
recognize the external SCSI device and automatically reset.
When an external SCSI device is connected to the external
SCSI connector on the rear panel of the computer, that device
becomes the end of the SCSI chain and must be terminated.
The system accommodates a combination of internal and external


SCSI devices, such as SCSI tape, CD-ROM drives, and hard


drives.
When an IDE hard drive and SCSI hard drive are both
installed, the system can boot only from the IDE hard drive.


Before you can install a SCSI device, you must first verify the
SCSI ID of the device and, if necessary, set the SCSI ID to a
new number. Be sure that each SCSI device on the SCSI chain
has a unique SCSI ID number.
Second, you must determine if the device ought to have
termination enabled or disabled. Set the termination if
necessary.
Hardware Reference Guide C-3