/ 17 August 2001

Communication through the ages

3500BC: Abstract signs; paper made from palm trees; oil and soot for writing

1184BC: Torch telegraphs transmit the fall of the town of Troy (fire signals)

360BC: Water telegraphs store detailed information transmitted by smoke signal

AD500: Indian astronomer Arya-Bhatta develops a system of decimal numbers

1794: C Chappe (France) develops an optical telegraph with its own alphabet

1809: Electric telegraph by Samuel T von Smmering, Germany (35 wires)

1840: Samuel FB Morse (United States) develops Morse code and improves telegraph

1844: Electrical switch (relay) automatically writes transmitted information

1861: Philipp Reis, a German teacher, invents the telephone

1876: Elisha Gray and Alexander Graham Bell (US) take out patents for telephones

1892: Telephone uses dial, first automatic telephone exchange (no operator)

1894: Wireless transmission of signals over 3km by the Italian Guglielmo Marconi

1902: Worldwide radio communication on ocean ships (Morse code)

1935: Multi-wire coaxial cables for communication purposes

1957: Russian Sputnik 1 first artificial satellite in orbit around the Earth: colour TV (systems SECAM and NTSC) ready to use

1960: Satellite launches become routine: first weather satellite

1961: IBM computers communicate over the telephone line, using modems

1966: Optical telephone connection over two-layer glassfibre cable

1968: Images sent over normal telephone line (one minute a TV screen)

1980: Videotext, cable television, videoconferencing, compact disc

1985: Satellite navigation (both military and civilian applications)