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In 1874, Alexander Grahan Bell built a phonautograph.A device that could draw vibrations of a human voice, used to teach his deaf students how to visualize sound. Bell’s phonautograph led him to consider that voice sounds might be conveyed electrically.
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Thomas Watson, Bell's assistant is an experienced electrician and model maker, who worked on Bell’s ideas. Then on March 10, 1876, Watson stood in the bedroom of Bell’s Boston apartment holding a receiver to his ear. In the lab down the hall, Bell spoke into a transmitter: “Mr. Watson, come here, I want to see you.” Watson heard every word; it was the first communication by telephone.
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As telephone transmissions expand across to bigger cities, American Telephone & Telegraph Company's (AT&T) insert inductors to reduce the loss of signal power.
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Bell System companies began installing switching systems and rotary-dial telephones. The dial makes it easier for customers to place calls without an operator. The finger wheel of the dial interrupts the current in the phone line, creating pulses that correspond to the digits of the number being called.
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Metal coaxial cable is used to carry a wide range of frequencies after AT&T develops the frequency multiplexing concept, in which frequencies of speech are shifted electronically among various frequency bands to allow several telephone calls at the same time.
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With the rapidly growing number of telephone customers, AT&T and Bell Labs develop the North American Numbering Plan, a system that assigns telephone numbers to customers in the United States and its territories as well as Canada and many Caribbean nations. The first three digits of a typical number identify the area being called; the next three, called the prefix, locate the closest central or switching office; and the last four digits represent the line number.
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AT&T introduces the Model 500 telephone, the first that combines a ringer and handset. The classic black rotary phone, featuring an adjustable volume control for the bell.
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Communications satellite Telstar 1 is launched by a NASA Delta rocket on July 10, transmitting the first live transatlantic telecast as well as telephone and data signals.The first international television broadcasts shows images of the American flag flying over Andover, Maine to the sound of "The Star-Spangled Banner." Telstar I remains in orbit for seven months, relaying live baseball games, images from the Seattle World's Fair, and a presidential news conference.
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The touch-tone telephone is introduced, with the first commercial service available in Carnegie and Greensburg, Pennsylvania, for an extra charge. The Western Electric 1500 model features 10 push buttons that replace the standard rotary dial. A 12-button model featuring the * and # keys comes out soon afterward and replaces the 10-button model.
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On February 16 the first 911 call is made in Haleyville, Alabama. Legislation calling for a single nationwide phone number for citizens to use to report fires and medical emergencies was passed by Congress in 1967, and in January 1968 AT&T announced plans to put such a system into place. The numbers 911 were chosen because they were easy to remember and did not include three digits already in use in the U.S. or Canadian area code.
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The first portable cell phone call was made by Martin Cooper of Motorola to his research at Bell Labs. Although mobile phones had been used in cars since the mid-1940s, Cooper’s was the first one invented for truly portable use
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The U.S. military begins using fiber optics to improve communications systems. Used to transmit data into light waves.By 1988 and 1989, fiber-optic cables are carrying telephone calls across the Atlantic and Pacific Oceans.
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Public tests of a new cellular phone system with more than 2,000 trial customers and mobile phone sets. The system, includes a group of small, low-powered transmission towers, each covering an area a few miles in radius
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Method of allowing people to make voice calls over the Internet on packet-switched routes. PC users find they can lower the cost of their long-distance calls.
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By the year 2000, more than a billion people all over the world had gone wireless—using cellular technology to talk and deliver text and photos on super-lightweight telephones smaller than a deck of cards.
