The invention of Telephones has had tremendous influence upon the world and has contributed greatly in setting the pattern of modern life. For countless mil-lions of people in cities and on farms the telephone is an indispensable tool of living; in the hour to hour conduct of business, in the administration of government, in minor and major emergencies and in main-taining family and community ties. With the airplane, Bell’s telephone has made the world smaller and brought the people round the globe closer together.
Alexander Graham Bell,’ the inventor of the telephone was born in Edinburgh on March 3, 1847 and was educated in Edinburgh and London Universities. Be-cause of failing health, he migrated with his father to Canada and two years later settled in Boston in U.S.A. Like his father and his grand father young Bell was then devoting his life to educating the deaf, and had acquired considerable knowledge of physiology of human speech and hearing. In 1873, he became Professor of Vocal Physiology at Boston University, but soon he devoted more and more of his time to the invention of multiple transmission of telegram over the wire. This was the time when the Duplex system had been invented and Bell hoped that his six, electrically vibrated, reeds would lead to a better system of multiple telegraphy.
It has come down to US that on the afternoon of 3rd June, 1875, one or his reeds got stuck to its electromagnet When Bell told his Assistant, Thomas A. Watson, to pluck the sticking reed, Bell found in the adjoining room, that the corresponding reed began to vibrate and produce a sound of the same pitch. From this simple pheno-menon, Bell deduced correctly that if a single sound could be transmitted electri-cally, so could complicated human speech. A circular piece of gold beater’s skin was stretched over a small cylinder into which one could speak and the skin was connect-ed to a reed over an electromagnet. After preliminary trials, the first complete sen-tence, “Mr. Watson come here I want you”, was spoken by Graham Bell to his assistant on 10th March, 1876.
Bell showed his equipment at the Philadelphia Exhibition of 1876, “The first step came in the next year when an out-door telephone line was run in Boston bet-ween the workshops of Charles Williams, (in which the first telephones were made by Watson), and William’s private residence in Somerville. Also in 1877, the first news dispatch was sent by telephone to the Boston Globe and this inaugurated the public use of the telephone. Thereafter the system expanded rapidly and the first tele-phone line and switch board for Commer-cial Service was installed at New Haven Connecticut in 1878 with 21 subscribers.
Telephone has come a long way since Alexander Graham Bell’s first crude ins-trument conveying human speech to only a few yards. Scientific progress has now overcome the barriers of distance, one by one, so that today there are no earthly limits to human speech. In a century’s time Telecommunication has developed into a major challenging technology. Transmission of intelligence from one place to another started with cod-ed signals over a single conductor. After undergoing different stages of technological achievements it is now possible to exchange information in forms of speech, television and telegraph signals almost around the entire globe. The process of development includes overhead/underground multi-channel carrier, high capacity coaxial cable, radio, H.F. VHF UHF micro-wave systems and latest of all the satellite communication system.
Successful attempts were made in 1962 to establish inter-continental communica-tion links via Telstar and relay satellites. Following this an international body known as INTELSAT (International Telecommu-nication Satellite) was formed in 1964 and Pakistan joined the organization as a mem-ber in 1965. A synchronous satellite moving with an angular velocity equal to that of the earth and located at 22,300 miles above the equator can provide a visual coverage of about one third of the earth’s surface. Thus, with 3 Synchronous Satellites located one each over Atlantic, Indian and Pacific oceans it is now possible to cover the entire globe.
In Pakistan the Satellite Earth station situated in Deh Mandro (35 miles from Karachi) started commercial operation on 15th November, 1972. The station provides international trunk service, public telegraph, leased teleprinter circuits, telex, voice-cast, radio photo and television services to a number of overseas countries. Through this station it has become possible for a Telex Subscriber in Pakistan to establish an overseas telex call by dialing directly from his machine. Live TV trans-mission around the world via satellite is now well known feature in Pakistan.