Network Cabling For Beginners
By Brandon Michael
What is cabling? Cabling is the foundation of your network, it is the medium that connects
all your computers and servers together and is probably one of the most important and often
overlooked items in business networks. The process begins by installing a twisted pair cable
made up of twisted wires surrounded by a protective jacket to connect data lines to a computer
or other network component.
The cables are run through ceilings and walls, out of sight, and link a data/phone drop to
a patch panel, or other termination block often installed within a rack in a server room or
telecom closet. Simply put, cabling is used to link together computers so they may form a
common network and communicate seamlessly with one another.
Anatomy of a typical office cabling installation:
• The cable begins its run from the central termination point or MDF (Main
Distribution Frame) and extends through the building to an outlet.
• The wall plate is terminated with a keystone jack (RJ-45 jack) rated for the
type of cable you are using.
• A patch cable is then used to connect the RJ-45 workstation area outlet
(WAO) to a computer or other device network capable device like an VOIP enabled phone.
• In the server room, MDF, or telcom closet, cables are terminated on a patch
panel and the corresponding numbers will be aligned to ensure easy identification. A floor
or wall mounted rack (typically 19? wide) may be used to house the patch panel depending on
the rooms design and space requirements.
• Finally, cable testing will be done to guarantee everything is in working
order, and certification testing may also be done to ensure compliance with industry standards
Once your office is properly cabled, efficiency is sure to increase and any additions
or changes to the cabling system will be easy to accomplish. So how do you get started? There
are several variables that must be considered before you begin. The first is what type of cable
will be used. There are various cable types and using the correct one is critical. As technology
advances, cable protocols are becoming faster and better.
• CAT3 - An unshielded twisted pair (UTP) configured to carry data up to
10 Mbit/s, with an attainable bandwidth of 16 MHz. Popular in the early 1990's but now considered
obsolete, it decreased in popularity due to the favoring of the high performing CAT5.
• CAT5 - A twisted pair high signal integrity cable that is capable of upholding
frequencies up to 100 MHz. Within a category 5 cables are 4 twisted pairs in a single cable
jacket. This use of balanced lines helps keep a high signal to noise ratio and considerably
reduces crosstalk interference.
• CAT5e - An improved version of Cat 5 that increases specifications for
far end crosstalk and all new installation should be at least CAT5e
• CAT6 - A cable structure for gigabit Ethernet and additional network protocol
that is backwards compatible with CAT3, CAT5, and CAT5e. CAT6 features stricter blueprints
for crosstalk and system noise. CAT6 provides performance up to 250 MHz.
• CAT6a - An improvement on CAT6, CAT6a operates at frequencies up to 500
MHz and can carry 10 Gbit/s operations up to a maximum distance of 100 meters. CAT6a also improved
conditions particularly in the area of crosstalk.
• CAT7 - Backwards compatible with CAT5 and CAT6. CAT7 introduces even more
exacting specifications for crosstalk CAT6 or CAT6a. Shielding has been added for individual
wire pairs, and the cable as a whole to achieve this. CAT7 has been created to allow 10 - gigabit
Ethernet over 100 meters of copper cabling, and is capable of running at frequencies up to
After you have selected your cable speed requirements you have to determine which jacket
type is required for your particular structured cabling installation:
• Plenum - Plenum is a type of cable jacket that is not only extremely fire
resistant, but also emits a far less toxic smoke should it catch fire. Some buildings and building
codes require this as a precautionary measure in case of fire. The name plenum refers to the
air conditioning, HVAC systems installed in buildings used to pull air out of once area and
blow it out at another.
If there happened to be toxic smoke in the air, imagine how quickly it could be pumped throughout
an office building with some of these large suction systems in use. With plenum jacketing,
toxicity levels after a catastrophic event like that would be exceedingly lower than with PVC,
however plenum can be almost twice as expensive as standard PVC.