Telegraph was the device invented by Samuel Morse and other inventors in 1830's and 1840's. It revolutionised long distance communication and worked by transmitting electrical signal by a wire laid between two stations.
Samuel Morse also developed set of dots and dashes for each alphabet of English language so that complex messages could be transferred via telegraph lines. Samuel Morse sent the first telegraph between Washington D.C to Baltimore in 1844. By 1866, telegraph lines had been laid between Europe and Atlantic.
