HP SureStore 220mx Optical Jukebox User's Guide

B-6 Appendix B
Operating This Jukebox on a SCSI Bus
A Brief Overview of SCSI
measures the voltage difference between the two signals. The differential
configuration retains more signal quality than single-ended and is not as
sensitive to noise, allowing for a longer cable length. The maximum
allowable length of a high-voltage differential bus is 25 meters (82 feet)
for all types of buses (narrow, wide, fast, Fast-20)
Low-voltage differential buses (Ultra 2) use less of a voltage difference
between the two signals used for each bus signal. The low-voltage
differential configuration also retains more signal quality than
single-ended and is not as sensitive to noise as either the single-ended or
high-voltage differential buses. The maximum allowable length of a
low-voltage differential bus is 12 metres (39.4 feet).
Connectors
50-pin connectors - narrow devices only
• 50-pin low-density clip Centronics-type (external)
This is a large connector that is similar to a printer cable. This type of
connector is gradually being replaced by the Micro D connector,
described below.
• 50-pin high density Micro D (using thumbscrews or small clips)
(external)
• This connector is similar to a D-type connector, but smaller and with
smaller pin holes placed closer together.
• 50-pin low-density ribbon (usually internal to the host)
68- pin connectors - some narrow and all wide devices
• 68-pin high density Micro D connector (external)
This connector is similar to a D-type connector, but longer and
slimmer and with smaller pin holes placed closer together. This
connector is becoming the most common.
• 68-pin high density ribbon (usually internal to the host)