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The humans (cavemen) began writing in caves about what they did day by day.
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When people started leaving the caves, they needed long distance communication, so they created the smoke signals. It was used in Northern America (each tribe has its own signaling system), Ancient China (the soldiers stationed at the great wall from tower to tower; It was used by alerted for danger, in both cases), and Vatican (to indicate the selection of new Pope).
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They also used pigeons for long distance communication. Were used by Persians, Romans, Greeks and Mughals. Were also used to transmit stock quotations from on city to another.
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was a first of its kind mail service: delivering messages, mails, newspapers and small packages by horseback using small relay stations. It is regarded as the first courier service.
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rIt started with James Clerk Maxwell in 1864 who showed mathematically that electromagnetic waves could propagate through free space.
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In 1876 Alexander Graham Bell invented the telephone.
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Heinrich Hertz established the existence of Electromagnetic waves. In 1888 he demonstrated that one could produce and detect electromagnetic waves.
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was used in maritime. Is derived from Greek word sema meaning sign and phero meaning bearer. It is a system conveying information by means of visual signals with hand-held flags, rods and disk. It is still used during underway replenishment at sea,
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was the greatest breakthrough in the field of communication. In the late 19th century gave birth to electric telegraphy. Morse code is still used globally as a mode of communication. The US discontinued the use of telegraph in 2006; India's BSNL owned telegraph service ended in 2013.
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using continues waves only; amplitude modulation was demonstrated for the transmission of voice and music but with little success.
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During world war 1 and 2 accelerated the development of radio for military, aircraft and land communication.
