A Telephone system is a communication instrument that transmits any voice / sound signals to far by locations by converting these sound signals in waves and receives and reconverts the same waves into sound signals/ voice˳ The telephone network is extended universally so if you want to talk to someone, you simply need to pick up the telephone system and dial a few digits˳ You are instantly connected to that person and both of you can have a 2 way conversation˳
Telephone systems were first introduced by Graham Bell over one hundred years ago, but it is still works on the same operating principle˳ To make a call, we need to first pick up the handset˳ This causes the telephone system to be connected to a routing network˳ By pressing the numbers present on the touch tone keypad / frequency generator, signals are passed down via phone line to the routing station˳ Here, each digit is identified as a unique combination of tone frequencies˳ The specific combination of digits causes a signal to be passed to other telephone systems causing it to ring˳ When that telephone is picked up, connection between the two telephone systems is achieved˳
The ear piece acts as speaker where as mouthpiece acts as a microphone˳ Sound waves from the user’s voice cause vibration to a thin plastic disc present inside the telephone system˳ This causes change in the distance between the plastic disk and another metal disk resulting in a varying electric current which is passed through the phone lines˳ The receiver on the other phone picks up this electromagnet current˳ These magnets cause diaphragm to vibrate which produces the sound /voice that initiated the current˳ An amplifier in the receiver end makes it easier to hear˳ When one of the phones is hung up the electric current get broken resulting in dis-connection of the telephone systems˳
Source by https://ezinearticles˳com/?Telephone-Systems—An-Overview-On-Operating-Principle&id=862525
