How stuff works (telephone) part 1

The RD is the disc and the metal cylinder wrapped in wire is the electromagnet

A telephone converts sound waves into electrical signals. When you talk into a telephone, the sound waves vibrate and spread out in every direction. The device turns these waves/vibrations into electrical pulses and at the other end of the phone, the device turns the electrical pulses back into sound waves. The process from which sound waves get converted into electrical waves takes place in a microphone. The microphone contains grains of carbon which electricity moves through. When you speak, the sound waves/vibrations move the grains in various patterns, altering the electrical signal which gets sent through the telephone line. At the other end of the line, an electromagnet is attached to a disc. The different electrical signals alter the strength of the electro magnet. The magnet makes the disc vibrate which move the air creating sound! Eureka!