Abstract :
Telecommunications is unique among technologies in its minimum demands upon the material and energy resources of nature. Throughout its history-particularly in the past century-it has found ways to increase its message handling capacity and reduce the unit costs by engineering developments, particularly by improved coding procedures. These coding procedures exploit both the single worldwide common medium of the radio spectrum and the multiple use of physical conductors employing cables and tubes and, more recently, by optical transmission to carry many messages simultaneously through common media. The cost of individual messages has continually decreased and the available media would be wasted rather than consumed if not used. Telecommunications may be substituted for many technologies such as physical transportation, which would consume scarce supplies of energy and materials. The paper is a historical outline of how the technology of telecommunications has expanded in the past century based on concepts as old as man´s discovery of speech, smoke signals, picture writing, and the alphabet.
