What material is used for telephone wires?
Telephone line
The vast majority of houses in the U.S. are wired with 6-position modular jacks with four conductors (6P4C) wired to the house's junction box with copper wires. Those wires may be connected back to two telephone overhead lines at the local telephone exchange, thus making those jacks RJ14 jacks. More often, only two of the wires are connected to the exchange as one telephone line, and the others are unconnected. In that case, the jacks in the house are RJ11.
Telecommunications cable
There are several types of telecommunications cable:Telecommunications power cable products, as described in Telcordia GR-347, consist of a stranded copper conductor used in AC/DC circuits up to 600 V that are insulated with non-halogen, limited smoke, polyolefin materials that are heat-resistant, moisture-resistant, and flame-retardant. These cables are provided as either Class B (standard) or Class I (flexible) products.Telecommunications power cable is intended for use in AC/DC distribution circuits, wireways, racks, and conduits installed in telecommunications Central Offices (COs), transmission stations, cell-tower sites, and other remote sites. These environments are normally dry, but cables may be placed in partially covered or protected porches, crawl spaces, or in underground vaults where water and high moisture levels can occur.