Twisted pair cable: what it is, types and purpose

Twisted pair cable consists of two insulated copper wires intertwined parallel to each other. Two or four pairs are placed in a common insulation. This reduces electromagnetic induction and crosstalk between them. The fields of the twisted wires neutralize the effects of their own and external magnetic fields. Twisted pair is used in telecommunications and LAN placement for the Internet.

Types of Twisted Pair Cable

Twisted pair cable differs in several parameters:

• the shape of the cross-section of twisted pair cable in the cross-section can be round or flat;
• the wires in the wire can be one or many;
• the way the cable is shielded and protection from interference electromagnetic radiation;
• the color of the sheath, which indicates the purpose of the wires.

Round wire universal, flat is designed for laying in the walls under the wallpaper, carpeting. However, it is more sensitive to interference.

Single-core wires are called monolithic wires. They are quite fragile, so they are placed in partitions. Multicore cables consist of bundles of cores in common insulation. This is a flexible wire that is easy to lay around bends. However, you should not use a cable longer than 100 m, because this design has a high attenuation factor.

Types of insulation against electromagnetic interference

All twisted-pair wires are classified into two types:

• shielded (FTP) - with electromagnetic shielding;
• Unshielded (UTP) - without protection against radiation.

Shielded twisted-pair cables are laid near electrical appliances, transformers and other sources of electromagnetic radiation. If there are no such devices and equipment nearby, you can use unshielded cable.

Shielded cables are classified as follows:

• U/FTP - each twisted pair is insulated with foil. This type of cable is suitable if the interference is insignificant.
• FTP - all twisted pair cable has a single foil sheath.
• S/FTP - a cable wrapped in foil and an additional protective braid.
• SF/FTP - each twist is wrapped in foil, there is an additional layer of fine wire mesh and another layer of foil. Such insulation gives maximum protection, so such a wire is used where there is high electromagnetic radiation.

For indoor insulation, twisted pair cable is used in a sheath made of PVC - polyvinyl chloride. This material is resistant to alkaline and acidic substances, it does not burn. For outdoor cable laying the jacket should be made of polyethylene. It does not deteriorate from temperature fluctuations, frost, ultraviolet.

The color of the sheath indicates the conditions in which the cable can be used:

• black - use the cable outdoors;
• gray - using cable indoors;
• orange - use cable in places with high fire danger.

Twisted pair cables differ in the speed of signal transmission. The most popular type of cable is Cat6/6a. Its ability to pass a signal up to 10 Gbit/sec. It is used to create local Internet networks, as well as video surveillance systems. There are cables with higher frequency and increased transmission speed up to 40 Gbit/sec.