Telecommunications closet
This is the service point housing all equipment associated with telecommunication wiring systems.
Its primary function is to serve as a termination point for the horizontal cabling system, but all transmission media terminates in this area.
The closet houses cross-connect and all associated electronic equipment, backbone and horizontal cabling, and associated pathways for the cable.
Most auxiliary equipment is also usually housed in this area, including security systems, key-entry systems, file servers, etc.
Depending on the size of the service area, the TIA/EIA-569 standard recommends at least one communications closet per floor. Specific closet sizes are also recommended, based on service-area size.
This ensures sufficient space for all connecting hardware, as well as enough room for service personnel to function without causing undue system disruptions.
Adequate climate controls, lighting, and power suppliers are also specified.

What to know before you buy
Conductors:
Copper cables have two types of conductors: solid or stranded. Solid-conductor cables are less expensive, have better conductivity, and are easier to terminate than stranded cables.
Additionally, solid-conductor cable is ideal for both backbone and horizontal wiring. Despite these advantages, however, solid-copper cable is comparatively inflexible, and breakage is likely if it is repeatedly bent or twisted.
That is why most twisted-pair cables today are made with stranded conductors, small-gauge wires twisted together to form a single conductor.
Stranded cable has two main advantages over solid-conductor cable: flexibility and durability.
It is flexible enough to bend back and forth, so it is much easier to work with, and it is far more resistant to damage from minor scratches or nicks that may occur during cable stripping.
Because the conductor wires are twisted, very little surface area is exposed to damage.
In comparison, one small scratch or nick on a solid-conductor cable may be enough to ruin it, because far greater surface area is exposed to damage from cutting or crushing forces.

Shielding:
Twisted-pair cable shields are metallic covers (usually copper or aluminum) that surround insulated conductors. They are constructed of foil, wire strands, or braided metal.
NEX1 recommends using shielded cable to protect data transmissions from external EMI, which can cause signal distortion or interference.
The quality of a shield depends on its surface-transfer impedance (STI), which indicates its ability to reduce EMI, especially at high frequencies.
The greater the reduction factor and the less external voltage that is picked up inside the cable, the better the shield.