<P> Rural and other telephones that were not on a common battery exchange had hand cranked "magneto" generators to produce an alternating current to ring the bells of other telephones on the line and to alert the exchange operator . </P> <P> In 1877 and 1878, Edison invented and developed the carbon microphone used in all telephones along with the Bell receiver until the 1980s . After protracted patent litigation, a federal court ruled in 1892 that Edison and not Emile Berliner was the inventor of the carbon microphone . The carbon microphone was also used in radio broadcasting and public address work through the 1920s . </P> <P> In the 1890s a new smaller style of telephone was introduced, the candlestick telephone, packaged in three parts . The transmitter stood on a stand, known as a "candlestick" for its shape, hence the name . When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook ." Previous telephones required the user to operate a separate switch to connect either the voice or the bell . With the new kind, the user was less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery, and magneto were in a separate bell box called a "ringer box ." In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out of the way place, since it did not need a battery or magneto . </P> <P> Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, separate from the cradle base that housed the magneto crank and other parts . They were larger than the "candlestick" and more popular . </P>

Who used the telephone when it was first invented