presented by
Rajitha.B

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Telecommunication History
OBJECTIVES
o History of telecommunications
o Early telecommunications
o Telegraph and telephone
o Radio and television
Computer networks and the Internet
 The history of telecommunication began with the use of smoke signals and drums in Africa, the Americas and parts of Asia.
 In the 1790s the first fixed semaphore systems emerged in Europe; however it was not until the 1830s that electrical telecommunications systems started to appear.
Evolution of Telecommunication Technology
• Today’s telecommunication technologies have evolved from the earliest smoke signals to almost instant global transmission of large amounts of data.
Telegraph and telephone
• A very early experiment in electrical telegraphy was an 'electrochemical' telegraph created by the German physician, anatomist and inventor Samuel Thomas von Sommering in 1809, based on an earlier, less robust design of 1804 by Catalan polymath and scientist Francisco Salvai Campillo.
• The first commercial electrical telegraph was constructed in England by Sir Charles Wheatstone and Sir William Fothergill Cooke.
• It used the deflection of needles to represent messages and started operating over twenty-one kilometres (thirteen miles) of the Great Western Railway on 9 April 1839.
A printing electrical telegraph receiver, and a transmitter key at bottom right.
• Cooke and Wheatstone patented it in May 1837 as an alarm system, and it was first successfully demonstrated on 25 July 1837 between Euston and Camden Town in London.
• Transatlantic telegraph cable
The site of the earliest message sent from Ireland to North America
• Grappling hook used for lifting the cable.
Early Signaling and Telegraphy
• Semaphore - a type of signaling, in which visual cues represent letters or words.
• Morse code - the transmission of a series of short and long pulses (dots and dashes) that represented characters.
• Duplexing - simultaneously transmitting a signal in both directions along the same wire.
• Multiplexing - simultaneously transmitting an indeterminate number of multiple signals over one circuit.
• 1856 - Western Union Telegraph Company was founded.
• 1861 – Over two thousand telegraph offices operated across the United States.
Telephone Technology
• 1878- The first telephone exchange opened in New Haven, Connecticut.
• Connected 21 separate lines.
• In 1889 Almon Strowger developed the automatic switch called the step-by-step.
• In 1896 he replaced the button-pushing method with a rotary dialer.
Invention of the telephone
• Alexander Graham Bell was the first to patent the telephone, an "apparatus for transmitting vocal or other sounds telegraphically", after experimenting with many primitive sound transmitters and receivers.
Telephone prehistory
Mechanical devices: mechanical devices for transmitting spoken words over a greater distance than that of normal speech.
• A different device, the tin can telephone, or 'lover's phone', has also been known for centuries.
• It connected two diaphragms with a taut string or wire which transmitted sound by mechanical vibrations from one to the other along the wire, and not by a modulated electrical current.
19th century 'tin can', or 'lover's' telephone
• Bell's Prototype Telephone
• Early telephone developments
Radio and television
• James Lindsay, in 1832, gave a classroom demonstration of wireless telegraphy to his students. In 1854 he was able to demonstrate a distance of 3km, using water as the transmission medium.
• It wasn't till 1900 that Reginald Fessenden was able to wirelessly transmit a human voice. In December 1901, Guglielmo Marconi established wireless communication between Britain and Newfoundland, which earned him the noble prize in physics in 1909 (which he shared with Karl Braun).
• In 1925, Scottish Inventor John Logie Baird publicly demonstrated the transmission of silhouette pictures at the Lond department store of Selfridges.
• In October that same year, Baird was successful in moving pictures with halftone shades, which were by most accounts the first true television pictures.
Wireless Technology
• 1894- Italian physicist Guglielmo Marconi a method of transmitting electromagnetic signals through the air.
– His invention relied on an induction coil.
Telecommunications History
Electronic Numerical Integrator and Computer (ENIAC)
• A multipurpose computer so large that it required its own 30 foot by 50 foot room.
Computer Networks and the Internet
• George Stibitz in 1940, September 11, was able to transmit problems using teletype to his Complex Number Calculator in New York and recieve computed results back in New Hampshire.
• However, it was't until the 1960s that researches started investigating packet switching, a technology that would allow data to be sent to different computers without first passing through a centralized mainframe.
• In 1983, the internet was invented. The Internet revolutionised all communication methods and in today's society is probably being used as the number one method of communication.
• Emails can be sent across the world in a click of a button, people can communicate across instant messenges (such as MSN) or talk instantly across the world using programs such as Skype.
• Facebook and Myspace had also revolutionised the way that people communicate today