Telephone is the largest, most widely used and popular medium of communication in the world. It is used to communicate, send E-mail, Fax, and for computer communication etc. with any other country. Alexander Graham Bell invented Telephone in 1875. Through many evolutions, the telephone invented by Graham Bell has reached to the modern dimensions and cordless, cellular and mobile-phone has been made.
How does telephone work
In every telephone set, there is a system of receiving and transmitting signal. The mouthpiece of a telephone is microphone, it is the transmitter and the ear-piece is a speaker, and is the receiver. There is a ringer for making the ringing sound and a dialing system in a telephone set. When we speak, the microphone of the mouthpiece converts our voice into electrical signal. This signal reaches to the ear-piece of another telephone through the telephone wire. The speaker of the earpiece converts the electrical signal into sound.
As a result, the caller or the called person can hear the sound and answer. This answer of the called person returns to the telephone set of the caller after being converted into electrical signal with the help of microphone of the mouthpiece and it is transformed into sound in the speaker of the earpiece of the caller, then the caller hears the speech of the called person. The electrical signal travels so fast through the telephone wire that it does not delay any single moment to transfer. Every telephone set is connected to the main regional office through wire. The connection with other telephone set is established through the regional head-office.
Cell phone or mobile phone: Cell phone or Mobile phone is the most popular and widely used medium of communication of present time. You can not only communicate with other but also, can play games, download music, songs, hear music, watch film and use intemet with the help of it. Besides, you can make cash payment, pay bill, check in at the airport and apply for the admission in a college or university using this phone. You can communicate from one corner of the country to another over phone.