The technology of communication over long distances was developed in gradual steps. The first significant step was the telegraph developed in the mid 1800s. (Before that no message traveled faster than a horse.) It sent an electric signal over wires that would produce a “buzz” in a receiver at the other end. Discuss: How could a monitone “buzz” be used to send verbal messages. The answer was the Morse code in which a combination of long and short “buzzes”, represented by dots and dashes, stood for the different letters as shown in this link.
http://en.wikipedia.org/wiki/Morse_code