Telecommunications cables are a type of guided transmission mediums. Cables are usually known to transmit electric energy ; however, cables in telecommunications fields are used to transmit electromagnetic waves; they are called electromagnetic wave guides. Telecommunications are based on transmitting modulated waves/signals through a medium and receiving them. When the distance between the transmitter and receiver is far, or an unguided medium transmission is used, antennas are used; otherwise, telecommunications cables are used in guided medium transmission.
Types
There are several types of telecommunications cable:
transmission lines when electric signals are transmitted;
waveguides when electromagnetic waves are transmitted;
optical fibers when light signals are transmitted.
Power Cables
Telecommunications power cable products, as described in Telcordia , 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 or Class I products.
Class B Cables — Class B type or standard power cables have a central copper conductor meeting the Class B definitions of standards document ASTM B8. The Class B conductor is constructed from a series of individual copper strands wound together in one or more helically wound layers. The individual strands are made of annealed copper per ASTM B3 or annealed tinned-copper per ASTM B33.
Class I Cables — Class I type or flexible power cables have a central copper conductor meeting the Class I definitions of ASTM B172. The Class I conductor is made of rope-lay-stranded members, with each member made of bunch stranded construction of small diameter individual strands. The small diameter individual strands are usually made of 24 AWG wires, soft or annealed per ASTM B3 or ASTM B33. In telecommunications power cables identified as Class I, the multiple strands of small-diameter wire strands may consist of 24 to 34 AWG strands wound together per ASTM B172.
Telecommunications power cable is intended for use in AC/DC distribution circuits, wireways, racks, and conduits installed in telecommunications Central Offices, 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. Telecommunications power cables use RHH or RHW type insulation materials as defined in for use in dry, damp, and wet locations. Products with dual RHH/RHW ratings can be used in all locations. The following cable location definitions are derived from the 2008 NEC.
Quality Systems
To maintain a continuing level of quality on the production of cable, suppliers typically administer a Quality Management System consistent with the latest issue of standards documents and or an equivalent alternate quality system satisfactory to the purchaser. Quality and reliability requirements are of two types: Product and Qualification. Testing and analysis criteria and QMS programs are given in for telecommunications power cables for telecommunications equipment in COs and within OSP facilities.
