HP SureStore Optical Jukebox 160ex Service Manual page 210

Theory of Operation
Configuring This Jukebox on a SCSI Bus
It is very important that the 68-pin to 50-pin cable is properly configured
to assure that the eighteen truncated lines are properly terminated.
Cable Lengths
Observe SCSI cable maximum lengths;
- 3 meters (9.8 feet) for the single-ended bus (remember, this is a fast
device)
- 25 meters (82 feet) for the differential bus.
Termination
• Refer to the documentation for the particular adapter being used to
see how to apply termination.
• Use active terminators to reduce noise sensitivity.
• Never terminate the bus at any place except the physical ends.
Terminating the bus in the middle will probably cause the bus to
become inoperable or operate in a state that could cause data loss.
• If devices are on both sides of the host computer adapter (such as
hard drives internal to the host computer and a jukebox external to
the host computer) make sure that there is no termination on the host
computer adapter. Termination must be only on the device inside the
computer that is farthest from the host adapter (on the bus) and the
last physical device on the bus external to the computer.
6-18 Chapter 6