For many years, used to send messages to the optical telegraph. Symbols transmitted by means of torches or mirrors reflecting the sun's rays.
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The latter device called heliograph. Later the invention of more sophisticated systems of the optical telegraph. Essentially all of the optical telegraph is a kind of relay for transmission of news in the form of conventional signals from one point to another by means of visible signs.
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For better visibility of signals and signs at each transmission towers were built high. Relationship of this kind was inconvenient, expensive, slow and suitable only for transmission of very short messages.
Only the use of electricity made possible by the telegraph and telephone, which provided a reliable and fast communication over long distances.
Now it is difficult to name any field of science or industry, which would not have used the radio. Radio engineering is widely used for communications, broadcasting, television, navigation, and location. On the use of radio methods and tools based Automation and Remote Control, Radio astronomy, sound, film, industrial application of high frequency currents for wood drying, hardening of steel and many other processes.