submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean. The firstsubmarine communications cables, laid in the 1850s, carried telegraphy traffic.
Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fiber technology to carry digital data, which includes telephone, Internet and private data traffic.
Modern cables are typically about 1 inch (25 mm) in diameter and weigh around 2.5 tons per mile (1.4 tonnes per km) for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore.