telegraphy

Transmission of messages along wires by means of electrical signals. The first modern form of telecommunication, it now uses computer terminals and printers for the transmission and receipt of messages. Telex is an international telegraphy network.

Overland cables were developed in the 1830s, but early attempts at underwater telegraphy were largely unsuccessful until the discovery of the insulating gum gutta-percha in 1845 enabled a cable to be successfully laid across the English Channel in 1851. Duplex telegraph was invented in the 1870s, enabling messages to be sent in both directions simultaneously. Early telegraphs were mainly owned by the UK: 72% of all submarine cables were British-owned in 1900.