Information Technology Reference
In-Depth Information
Basic Structured Cabling Terminology
In order to talk about intricacies of a subject such as structured LAN wiring, we need
a common lexicon. Unfortunately, the cabling industry has developed as a combina-
tion of many technologies and disciplines, each with its own vocabulary and termi-
nology. Many of the twisted-pair wiring techniques we use in today's LAN wiring
were initially the domain of the telephone industry. In fact, the styles of wire, connec-
tors, terminations, and even color codes that we use today were developed decades
before anyone considered using telephone-type wire for digital networks. Many of
these telephone terms have been made directly a part of LAN wiring vocabularies.
On the other hand, all of the terms that are used for LAN wiring signals, cables, stan-
dards, and termination equipment come from the computer networking industry.
Now that we are “pushing the envelope” into the stratosphere of LAN speed per-
formance, we are beginning to encounter even newer terms that may be unfamiliar
to many of us, but would make any radio-frequency (RF) engineer smile.
In this topic, we will attempt to be as consistent as possible in terminology so
that you will always know what we mean by a particular word or phrase. We will
particularly avoid jargon that is used only by a narrow segment of the industry, other
than to explain special meanings of terms that you may encounter when dealing with
contractors and suppliers. It will be necessary to use some terms almost interchange-
ably, such as the terms wiring and cabling. To not do so would be a disservice to you
the reader, because you will certainly encounter all of these interchangeable terms in
your everyday work. We will always try to be clear in our meaning.
A complete glossary appears at the end of this topic. Each time we introduce a
new term, we will define it. Some LAN wiring terms are common words or phrases
that have a particular meaning in the cabling industry. For the most part, after these
are introduced, we will simply use them with their special meanings, without
emphasis. In a few instances, special words or terms will be capitalized. Examples
of this are Channel and Permanent Link, which are very specific terms used in one
of the service bulletins that revise, amplify, or clarify EIA/TIA standards. Such terms
are not in general use, and their meanings are specific to the definitions in a stan-
dards document. Acronyms and abbreviations are also part of the world of LAN
wiring. The common terms will be formally introduced only once, although the less
common ones may have their definitions repeated at the beginning of a section.
Specific, commonly accepted terms can be very useful in providing shortcuts to
understanding and explanation of a complex system such as LAN wiring. However,
jargon that is peculiar to a narrow part of an industry can be tedious and even con-
fusing. We will therefore stick to more commonly used computer networking terms
that are widely understood. If you have a technical background in a specific area,
