Invention of the telephone

Invention of the telephone

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An actor portraying Alexander Graham Bell speaking into an early model telephone.
The invention of the telephone is the culmination of work done by many individuals, the history of which involves a collection of claims and counterclaims. The development of the modern telephone involved an array of lawsuits founded upon the patent claims of several individuals. This article covers the early years 1844–1898, from conception of the idea of an electric voice-transmission device, failed attempts to use "make-and-break" current, successful experiments with electromagnetic devices by Alexander Bell and Thomas Watson, to commercially successful telephones in the late 19th century.
The origins of the telephone date back to the non-electrical string telephone or "lover's telephone" that has been known for centuries, comprising two diaphragmsconnected by a taut string or wire. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone, a children's toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy was that a diaphragm can collect voice sounds from the air, as in the ear, and a string or wire can transmit such collected voice sounds for reproduction at a distance.

Mobile phone

From Wikipedia, the free encyclopedia


"Cell Phone" redirects here. For the film, see Cell Phone (film). For the Handphone film, see Handphone (film).



The Qualcomm QCP-2700, a mid 90s candybar style phone, and an iPhone 4S, a current production smartphone.
A mobile phone (also known as a cellular phone, cell phone and a hand phone) is a device that can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile phone operator, allowing access to the public telephone network. By contrast, a cordless telephone is used only within the short range of a single, private base station.
In addition to telephony, modern mobile phones also support a wide variety of other services such as text messaging, MMS, email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and photography. Mobile phones that offer these and more general computing capabilities are referred to as smartphones.
The first hand-held mobile phone was demonstrated by Dr Martin Cooper of Motorola in 1973, using a handset weighing around 1 kg.^[1] In 1983, the DynaTAC 8000xwas the first to be commercially available. In the twenty years from 1990 to 2011, worldwide mobile phone subscriptions grew from 12.4 million to over 5.6 billion, penetrating the developing economies and reaching the bottom of the economic pyramid.^[2][3][4][5]