Telecommunications: The Las, and the Next, 50 Years

Publisher Summary This chapter discusses the past and next 50 years of telecommunications. The present-day world telecommunication network is the most complex, extensive, and costly of mankind's technological creations. In the early 1940s, telecommunication services in the United Kingdom were predominantly for telephone speech and telegrams, with limited low-speed data and facsimile transmission. Telegrams were transmitted using teleprinters operated at 50 bits/s, corresponding to the speed of the average typist. Video transmission hardly existed except for a few miles on cable pairs in London. The war years, 1939–1945, gave a strong impetus to the development of radio and electronic technology for military purposes that later proved of value for civil telecommunications. By 1986, there were more than 65,000 km of 140 Mbit/s optical fiber systems in operation in the British Telecom intercity network, and 565 Mbit/s systems were beginning to come into service. Progress has been made to reduce the time and improve the quality of facsimile transmission; the six minutes required to transmit an A4 page in the 1960s was reduced to 3 minutes by 1976. Many laboratories are now exploring optical switching with a view to closer integration with optical transmission and ultimately faster, more flexible, and lower cost telecommunication systems. The continuing development of information technology and new services—such as the video library—will require data bases of even larger capacity and fast access, while the effective implementation of the virtual reality concept requires data bases larger by several orders of magnitude than have been achieved so far.