For the organization of most data networks, computer or telephone, cables are used. Such networks are called wired. In recent years, they are most often laid using a special type of cable called “twisted pair”. The name reflects the type of arrangement of the conductors relative to each other. Twisted pair is two insulated conductors twisted together with a certain twisting pitch. Typically, these two wires have another layer of insulation.
There are cables that have two, four, eight pairs of conductors under one sheath. Nevertheless, such a cable is called “twisted pair”, although there are several pairs themselves. Unshielded and
shielded cables are available depending on the type of protection
. Shielding reduces the effects of external and internal interference, increases the reliability of the connection, reduces the number of errors. To ensure integrity in case of excessive bending and tearing, the screen along the entire cable length is connected by a special uninsulated drain wire. Shielded twisted pair cable provides a high transmission speed, partially eliminates the influence and interference from other objects.
Screens can take the form of a mesh, braid, continuous foil coating. There are cables with double protection, while foil is wound over the mesh braid. According to international practice, this type of conductor has the following designation: unshielded twisted pair - UTP, shielded - STP. If the cable has a common protective shield, but the individual pairs are not shielded, then such a wire is also classified as unshielded. Terminal equipment uses different types of cables. Which one do you need, see the passport or description.
Depending on the structure of the conductors used, twisted pair can be single-core or multi-core. A single- core cable consists of one large-diameter wire; a multi- core cable is a bundle of thin wires. The scope of their application is different. Single core have greater rigidity, bend poorly, with repeated bends can break. Them
used for laying in walls, pipes and ducts, followed by institution in the outlet. Stranded twisted pair has good flexibility, but does not tolerate connection to outlets. This type of cable is used to connect terminal devices to outlets.
The outer shell of the conductors serves to protect them from moisture and mechanical damage. It has a different thickness and is made of different materials. According to European standards, only cables that do not emit smoke and do not burn are suitable for external installation.
To facilitate the work, different colors are used for conductors for various purposes. For example, the black color of the outer sheath is found in the cable for external laying, orange means that the sheath material is off, and the color of the inner conductors is usually gray. Cables, consisting of twisted pairs, can have different shapes: round or flat (for laying under the floor).