The Land connected telephone is a verbal, electronic device mostly used for long distance. It allows people from all around the world to have two way conversations. The energy transfer which takes place in a land connected telephone is sound-electric-sound.
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Switch: To connect and disconnect the phone from the network. This switch is generally called the hook switch and connects you to the network when you lift the handset.
Speaker: Transfers the electrical pulses which come through the phone into sound waves so you can hear the person on the other end of the line.
Microphone: Transfer’s the sound waves from someone’s voice into electrical energy which then travels to the person on the other end of the line.
Duplex coil: To prevent the person talking to hear their own voice through their own speaker.
Ringer: Makes a pleasant ringing noise when someone is trying to make contact.
Keypad: Allows you to dial the number of the person you wish to talk to.
A telephone mouthpiece contains a thin metallic coating separated from an electrode by a thin barrier which connects to a wire carrying an electric current. When a person speaks into the mouthpiece, the acoustic vibrations from their speech push the metallic coating slightly closer to the electrode, resulting in variations in voltage and therefore a speedy conversion from sound to electric energy. The electric pulses are run through a wire to the speaker on the other end, where electric pulses are converted into sound energy again.
Over time, the telephone has evolved in its efficiency, price and design. The telephone now has a wider span of contact due to advances in technology. People can now make a call within seconds to anyone nationally and internationally. National calls are now much quicker due to the advances of the broadband cables, and international calls are much clearer and faster due to advances in satellite technology.