Houlin Zhao Deputy Secretary-General, ITU ICT Innovation and ITU International munication Union At the 10th China Beijing International High Tech Expo International Forum on China High-Tech Development Beijing, 25 May 2007 munication system development 1837: Invention of telegraph 1876: Bell patent his telephone invention 1895: First radio relay system 1902: First radio transmissions of the human voice 1920: Sound-broadcasting by pany 1957: First satellite 1963: First munications satellite Telephone switching systems 1935-1950: Cross-bar 1950-1960: Research electronic switching 1960: Software production 1965-1975: 1st generation, space-division SPC 1970-1985: Time-division digital centralized SPC 1980-: Time-division digital distributed SPC Evolution of munication systems puter generations 1945: 1st generation, with tubes 1958: 2nd generation, with transistors 1963: 3rd generation, with integrated circuits 1975: 4th generation, with microprocessors 1990s: 5th generation, with artificial intelligence Semi-conductor / solid ponents generations 1950: Transistors 1970: Integrated circuits 1975: LSI (Large Scale Integration) 1980: VLSI (Very Large Scale Integration) Evolution puter technologies Telegraph: Morse Code telegraph telex (wireless) (wired + wireless) Telephone: analogue digital IP Telephony Network Switch: manual, automatic (mechanic), SPC (circuit s
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