1900 - 2000 A.D. 1904 First broadcast talk 1918 Invention of the short-wave radio 1929 Invention of television in Germany and Russia 1941 Invention of microwave transmission 1946 Long-distance coaxial cable systems and mobile telephone services are introduced in the USA. 1957 First data transmissions over regular phone circuits. At the beginning of the story of today's global data networks is the story of the development of In 1955 President Eisenhower announced the USA's intention to launch a satellite. But it in the end it was the Soviet Union, which launched the first satellite in 1957: Sputnik I. After Sputnik's launch it became evident that the Cold War was also a race for leadership in the application of state-of-the-art technology to defense. As the US Department of Defense encouraged the formation of high-tech companies, it laid the ground to Silicon Valley, the hot spot of the world's computer industry. The same year as the USA launched their first satellite - Explorer I - data was transmitted over regular phone circuits for the first time, thus laying the ground for today's global data networks. Today's satellites may record weather data, scan the planet with powerful cameras, offer global positioning and monitoring services, and relay high-speed data transmissions. Yet up to now, most satellites are designed for military purposes such as reconnaissance. 1969 ARPAnet was the small network of individual computers connected by leased lines that marked the beginning of today's global data networks. An experimental network it mainly served the purpose of testing the feasibility of In 1969 ARPANET went online and linked the first two computers, one located at the University of California, Los Angeles, the other at the Stanford Research Institute. Yet ARPAnet did not become widely accepted before it was demonstrated in action to a public of computer experts at the First International Conference on Computers and Communication in Washington, D. C. in 1972. Before it was decommissioned in 1990, In the USA it was already in 1994 that commercial users outnumbered military and academic users. Despite the rapid growth of the Net, most computers linked to it are still located in the United States. 1971 Invention of 1979 Introduction of 1992 Launch of the |
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1000 B.C. - 0 900 B.C. A postal service is used for governmental purposes in China. 500 B.C. In ancient Greece trumpets, drums, shouting, beacon, fires, smoke signals, and mirrors are used for message transmission. 4th century B.C. Aeneas Tacitus, a Greek military scientist and cryptographer, invented an optical communication system that combines water and beacon telegraphy. Torches indicated the beginnings and the ends of a message transmission while water jars were used to transmit the messages. These jars had a plugged standard-size hole drilled on the bottom side and were filled with water. As those who sent and those who received the message unplugged the jars simultaneously, the water drained out. Because the transmitted messages corresponded to water levels, the sender indicated by a torch signal that the appropriate water level had been reached. The methods disadvantage was that the possible messages were restricted to a given code, but as the system was mainly used for military purposes, this was offset by the advantage that it was almost impossible for outsiders to understand the messages unless they possessed the codebook. With communication separated from transportation, the distant became near. Tacitus' telegraph system was very fast and not excelled until For further information see Joanne Chang & Anna Soellner, Decoding Device, 3rd century B.C. Wax tablets are used as writing material in Mesopotamia, ancient Greece, and Etruria. 2nd century B.C. In China paper is invented. 1st century B.C. The use of codices instead of scrolls - basically the hardcover book as we know it today - is an essential event in European history. To quote accurately by page number, to browse through pages and to skip chapters - things that were impossible when reading scrolls - becomes possible. In the computer age we are witnesses to a kind of revival of the scrolls as we scroll up and down a document. The introduction of hypertext possibly marks the beginning of a similar change as has taken place with the substitution of scrolls with codices. |
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Chappe's fixed optical network Claude Chappe built a fixed optical network between Paris and Lille. Covering a distance of about 240kms, it consisted of fifteen towers with semaphores. Because this communication system was destined to practical military use, the transmitted messages were encoded. The messages were kept such secretly, even those who transmit them from tower to tower did not capture their meaning, they just transmitted codes they did not understand. Depending on weather conditions, messages could be sent at a speed of 2880 kms/hr at best. Forerunners of Chappe's optical network are the For more information on early communication networks see |
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Backbone Networks Backbone networks are central networks usually of very high bandwidth, that is, of very high transmitting capacity, connecting regional networks. The first backbone network was the |
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