cable

cable originally wire cordage of great strength or heavy metal chain used for hauling, towing, supporting the roadway of a suspension bridge, or securing a large ship to its anchor or mooring. Today a cable often refers to a line used for the transmission of electrical signals. One type of electric cable consists of a core protected by twisted wire strands and suitably insulated, especially when it is used to cross oceans undersea; a message transmitted by cable is known as a cablegram or cable. France and England were first successfully connected by submarine telegraphic cable in 1845. The first permanent transatlantic cable was laid in 1866 by Cyrus West Field , although demonstrations of its possibility had been made in 1858. The first telephone message was transmitted from New York to Philadelphia in 1936; the first transatlantic telephone cable was laid in 1956.

The coaxial cable, which is virtually immune to external interference, consists of two concentric conductors separated by an insulator; the current in the inner conductor draws the current in the outer conductor toward the center rather than letting it dissipate outwards. Because they can carry a large number of signals simultaneously, coaxial cables are also used in cable television systems. The newest form of cable is the fiber-optic cable, developed in the 1970s. Instead of a copper conductor, a silica glass fiber carries digitized signals as pulses of light.

The insulated wire that conducts electricity from generator to consumer is also called a cable; it often contains multiple conductors and must be of sufficient gauge to carry large currents. Its insulation must withstand high voltages.

ca·ble / ˈkābəl/ • n. 1. a thick rope of wire or nonmetallic fiber, typically used for construction, mooring ships, and towing vehicles. ∎  the chain of a ship's anchor. ∎  Naut. a length of 200 yards (182.9 m) or (in the U.S.) 240 yards (219.4 m). ∎  (also cable molding) Archit. a molding resembling twisted rope. 2. an insulated wire or wires having a protective casing and used for transmitting electricity or telecommunication signals. ∎  a cablegram. ∎ short for cable television. • v. [tr.] 1. contact or send a message to (someone) by cablegram. ∎  transmit (a message) by cablegram. ∎  [intr.] send a cablegram. 2. (often be cabled) provide (an area or community) with power lines or with the equipment necessary for cable television. 3. Archit. decorate (a structure) with rope-shaped moldings. ORIGIN: Middle English: from an Anglo-Norman French variant of Old French chable, from late Latin capulum ‘halter.’

cable Wire for mechanical support, for conducting electricity or carrying signals. In civil and mechanical engineering, a cable is made of twisted strands of steel wire. They range in size from small bowden cables to massive supporting cables on the decks of suspension bridges. In electrical engineering, a cable is a conductor of electricity and consists of one or more insulated wires, which may be either single or multi-stranded. They range greatly in size, from cables used for domestic wiring to the large, armoured underwater cables. These are used for telephone, radio, television and data signals. In a coaxial cable, one conductor is cylindrical and surrounds the other. Optical fibres carry signals in the form of coded pulses of light.