A telephone is a device that helps people to talk directly and simultaneously with one another across long distances. Telephone is also referred as “phone.”  Sound is converted into electronic signals that are transmitted through cables over long distances and after receiving the signals the receptor’s device replays it in audio form.  In 1876, Alexander Graham Bell invented the first device to communicate between two individuals who are not in the same vicinity. It includes a microphone to speak into and an earphone which reproduces the voice in a distant location. It contains a ringer and dial too.  Ringer makes sound to announce an incoming telephone call.  Dial is used to enter a telephone number when making a call to another telephone. Telephones appear in various styles, shapes and sizes. The earliest telephones had rotatory dial which were later replaced by push-button dial. A telephone connected permanently by a pair of wires to the telephone network is called landline telephone. When the device is portable and communicates by radio transmissions, it is known as mobile telephone. Telephones have become essential in all walks of life.