There are many different aspects about SCSI that can be confusing to someone new to the
technology--and even someone not new to it.
Of all of the aspects of SCSI
that sometimes cause a bit of difficulty, cables and connector issues are probably the
worst. Unlike the IDE/ATA world, where there are a handful of different cable types, with
SCSI there are literally dozens of different types of cables! It is difficult to
even describe all of the options available. This is a result of the flexibility of the
SCSI interface--more choice means more options, and hence, more decisions. 
In this section, I describe the cable and connector hardware most commonly seen on the
SCSI interface. There are many different types of cables, and many types of connectors,
and to some extent they can be "mixed and matched"--meaning that you may find
different types of cables for each connector type and vice-versa. Therefore, I begin by
first discussing general cabling issues, and then describing the most common technologies
found for cables, and then the same for connectors. I then cover the specifics of the
three most common general categories of cables: narrow, wide, and LVD cables, and provide
pin-out listings for the signals they use as well. I then explain the single connector
attachment method of connecting SCSI drives, talk about adapters, and discuss different
ways that the SCSI bus is terminated.
Note: I have to state
"up front" that I do not describe every type of SCSI cable and connector that
exists in this section, just the most common ones. There are so many types of
cables, including some that are created for very particular applications, that I couldn't
even begin to describe them all. By reading this section you will know most of what you
need to know about SCSI cables and connectors. However, if you are looking to buy SCSI
cables, the most important thing you should look for is a quality vendor that
will help you choose the correct cable for your application. SCSI cables can be expensive;
a reputable vendor will be able to ask the correct questions to ensure that you get the
hardware you need.
Next: General Cable and Connector Issues