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Secondary Project 11-14's Worksheet 1 The first steps to a Connected Earth Telecommunications is the science and technology of transmitting information electronically over distance, using radio signals or electrical or optical lines. Telecommunications isn't a modern idea. The word comes from the Greek word 'tele' meaning 'far away'. You are going to explore the building blocks that led to mass telecommunications and consider the impact of discoveries that have profoundly changed our world. Bounce back in time 1. Use the timeline on this and the next page to trace the development of the first steps of communications. Make notes as you read it on the developments you feel are most significant in preparation for the questions in the following worksheets. 1729 Gray discovers conductivity. He shows that static charges of electricity could be conducted by some materials but not others. 1750 1753 Morrison suggests using 26 wires (one for each letter of the alphabet) to send messages over long distances. 1774 Lesage sets up a simple telegraph between two rooms using 24 wires. 1793 Chappe brothers develop the 'tachygraph' - a system of 'mechanical semaphore arms' that can form different shapes to send messages. 1800 1798 Salva proposes long distance electric telegraph lines, overhead, overground and running under the sea. 1809 Sommering develops telegraph of 35 wires (one for each number and letter). 1820 Oersted places compass next to electrical wire - the compass needle moves at right angles to wire when electric current on - links electricity and magnetism. 1820 Ampere discovers how electric currents behave and how to measure them. 1832 Schilling coils electrical wire around magnetised needle - it swings one way or another, depending on direction of current. 1833 Gauss and Weber send signals over 2 km - moving needles point to letters 1 Secondary Project 11-14's Worksheet 1 1835 Morse builds electromagnetic pendulum carrying a pencil in contact with a moving strip of paper. 1837 Cooke and Wheatstone develop needle-telegraph system - needles point to letters to spell out words and successfully sends message over several miles. 1842 First commercial telegraph service from London Paddington to Slough. 1847 An inelastic latex substance called Gutta Percha (an ideal electric wire insulator) makes undersea cable laying a possibility. 1850 Mid-1850s Morse develops system to hear telegraph signal and code to carry information - trained operators can translate incoming messages quickly. The laying of the first translantic cable 1858 Successful but short-lived telegraph cable laid across the Atlantic. 1861 Reis creates a transmitter diaphragm to send music electrically for the first time. 1866 Cable across the Atlantic completed after several failed attempts. 1870 UK telegraphs taken over by the Government / Post Office. Lines start to reach many more towns and many villages. 1872 Telegraph starts to be used in businesses in offices, banks, gentlemen's clubs and leading hotels. 1874 Baudot develops 'multiplex' telegraph system - four messages can be sent at the same time. 1875 Bell develops a prototype telephone that sends and reproduces complex sound. A year later he develops first telephone using speech. 1877 First telephones arrive in the UK. 1878 Investors obtain British rights to the invention, and begin to sell telephones for private use. 1879 UK's first public telephone exchange - an exclusive club of eight subscribers. 1880 First telephone directory with 250 subscribers. 1884 Telephone line links London to Brighton. 1891 First submarine telephone cable between England and France. Strowger develops automated switching machine for the telephone exchange - callers no longer need to be connected manually. 2