Data cable has different purposes (establish physical communication between networks, interconnect analogue or IP telephones with communication centres...). The composition of data cables of several conductors (made of copper or copper clad aluminium), isolating each conductor with a layer of coloured polyethylene so it can be easily identified and it also protects it from oxidation. These conductors are twisted in pairs, in order to improve the integrity against electromagnetic interference. The sheath will determine the protection of the cable in different environments.