This module deals with category 5, or CAT5 unshielded Twisted Pair cable. As shown at the right, Twisted Pair consists of a series of small copper wires, each with it's own colour-coded jacket, which are twisted together in pairs, and encased within a larger cable jacket. The wires themselves may be either solid or stranded. The outer jacket covering comes in different colours, which is useful in networking to differentiate between what the cable is being used for, such as for creating crossover or patch cables, also described in this module. Category 5 cable is twisted into pairs as this twisting works to eliminate distortion of the data being transmitted, aids in limiting loss of data called attenuation, and rejects electrical interference or "noise". There are generally 4 twists per inch of wire, and eight wires, or four pair.

Category 5 cable is twisted into pairs as this twisting works to eliminate distortion of the data being transmitted, aids in limiting loss of data called attenuation, and rejects electrical interference or "noise". There are generally 4 twists per inch of wire, and eight wires, or four pair.

Cable Types:

The main two types of CAT 5 cable that this module covers are solid core and stranded. The differences between these materials are explained below. The third type of cable described below, Plenum-rated cable, is very expensive and has a very specific use.

• Solid Core Cable: Use this cable for applications that will not be moved around very much after installation, for example: "Horizontal cabling" - the name given to cabling that runs within the walls, ceiling, and floors of structures, back to the network hub.
  
  Solid core cable feels and is more rigid. This quality makes it better suited to "in-wall" applications, and less suited to "every-day" applications. If used, for example, as a patch cord, where it would be subject to bending due to being regularily handled and moved around, the cable may work-harden and break. For this reason, DO NOT use solid core cable for patch cords!! It is not designed to function for patch-cord material, and for this reason, will not do so.
  
  Solid core cable is also more brittle than stranded cable - be careful not to nick it when working with it, or it may break, making it unusable. It is possible that you may not even be able to see the break, which could make for a very difficult trouble-shooting problem when the network doesn't work.
  
  
• Stranded Cable: Unlike the solid core cable, multiple strands make this cable very flexible, not subject to work-hardening under regular movement and bending, and thus a much better material to use for the creation of patchcords and crossover cables.
  
  
• Plenum-Rated Cable: Generally speaking, Telecom and Network cables are highly toxic when they burn in building fires, which can cause additional problems for humans in the structures. Plenum-rated cable is designed for its less-toxic characteristics when on fire, and is thus suitable for installing in existing ductwork within buildings. Should the building catch fire and this cable burn, it will be less toxic for the building inhabitants still present, which could mean the difference for them between life and death. If this cable type meets your requirements, it is suggested that you measure very carefully and plan for exactly what your needs are, as it costs roughly twice as much as the other, more common, cable types.

TIP: When purchasing cable, always plan your purchases so that you will have ample amounts each of the cable types that you require. Handle both cable types with care, and use the appropriate cable for the job that you are doing!

Use of Cable standards:

When installing an ethernet network, it is important to stick to standards. While it is *possible* to attach the wires in any order and have the network work (provided that you used the same order on each end), it is certainly not recommended. Cables for different purposes are made to either the A or B standard. If a network is *not* built to those standards then it is not possible to use commercially available products such as patch cables and crossover cables, as a non-standard network will not be able to communicate using standardized cable products, which means that someone constructing a non-standard network would have to create *each* piece, from scratch, to match their design, or it is likely that the network would not function. Therefore it is HIGHLY RECOMMENDED that the standards be adhered to when building a network.

TIP: Use the cable standards! You'll be happy you did!