Information Technology Reference
In-Depth Information
This chapter will describe the various types of connectors that are used to terminate
cable ends. We have previously covered station cable termination, so this section
will concentrate on the 8-pin modular plugs that are used on freestanding cables
such as patch cords and user cords (sometimes called user cables). We will also look
at the user cords that are used in the work areas and the equipment rooms for con-
nection to network hardware.
This is a good time to point out the distinction between “cables” and “cords”
as used here and in many of the standards. Obviously, both cables and cords used
in telecommunications employ jacketed, multi-paired cables, but it is customary to
refer to the flexible, stranded-wire, plug-terminated cables that connect to worksta-
tions, hubs, and patches as “cords.” This is the convention followed by most of the
standards. The usage rule is probably more consistent when referring to patch cords,
which are inevitably referred to as “cords.” The terms “user cord” and “user cable”
are used interchangeably, as are the terms “equipment cord” and “equipment
cable.” For consistency in this topic, we have tried to use the word “cable” to refer
to any solid-conductor cables that are terminated in a jack or punchdown, and use
the word “cord” to refer to any stranded-conductor cables that are terminated in
modular plugs. With regard to coax cables, they are normally referred to as
“cables,” regardless of their location. By the same token (pun intended), IBM data
connector cables are normally referred to as “cables.” Both of these last cable types
are identical in composition and termination whether they are used in the wall or
by the equipment user.
We will primarily cover modular cable connectors in this chapter. Coax connectors
and IBM data connectors are considered legacy connectors and are covered in
Appendix B. Fiber-optic connectors are described in Chapters 6, 7, and 11 and will
not be covered here. Of the three other types of connectors, the modular connector
is obviously the most favored for modern LAN wiring, because of the increasing use
of unshielded twisted-pair cable. Coax has long been used for traditional Ethernet
and ARCnet LANs, but is gradually being phased out in most locations. The data
connector is an important connector in shielded twisted-pair wiring systems, and it
is now included in the TIA-568-C standard.
Modular Connectors
The modular connector used in LAN systems is the same connector that is used in
modular telephone wiring systems. This connector is available in several possible
