telephone

Telephone communication is a communication technology that uses the medium of "electricity" to transmit language through the mutual conversion of acoustic energy and electric energy. The simplest way for two users to communicate is to connect two telephones with a pair of lines.
When the speaker picks up the phone and speaks into the microphone, the vibration of the vocal cords excites the air to vibrate, forming sound waves.
Sound waves act on the microphone to generate current, which is called voice current.
Voice current is transmitted to the receiver of the other party's telephone along the line.
The receiver is just the opposite of the microphone-it converts the current into sound waves and transmits them to people's ears through the air.