HP 220mx HP SureStore 220mx Optical Jukebox User's Guide - Page 90

Operating This Jukebox on a SCSI Bus The SCSI Bus and This Jukebox Mixing Single-Ended, High-Voltage Differential, and Low-Voltage Differential Devices On a low-voltage differential (LVD) bus, if the jukebox senses a single-ended device on the bus, the bus will be operated as a single-ended bus. You must not mix high-voltage differential buses with either low-voltage differential or single-ended buses. High-voltage signals are on different pins and may damage low-voltage differential circuits. Cable Lengths This jukebox can use either a single-ended or low-voltage differential bus. When using a single-ended bus, you have 8.50 feet (2.59 metres) available for an external bus. (3 metres allowable minus 0.41 metres for internal cabling.) If you are using a low-voltage differential bus, you have 38.04 feet (11.59 metres) available for an external bus. (12 metres allowable minus 0.41 metres for internal cabling.) Termination • Refer to the documentation that comes with your particular adapter to see how to apply termination. • Use active terminators on single-ended buses to reduce noise sensitivity. Use low-voltage differential terminators if using a low-voltage differential bus. If you have a multimode (SE/LVD) host adapter, you can use SE/LVD terminators. These terminators can sense which mode is being used. • 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 bus 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 bus adapter. Termination must be only on the device inside the computer that is farthest away (on the bus) from the host bus adapter, B- 10 Appendix B