The telephone, or phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other. Developed in the mid-1870s by Alexander Graham Bell and others, the telephone has long been considered indispensable to businesses, households and governments, is now one of the most common appliances in the developed world. The word "telephone" has been adapted to many languages and is now recognized around the world.
All modern telephones have a microphone to speak into, an earphone (or 'speaker') which reproduces the voice of the other person, a ringer which makes a sound to alert the owner when a call is coming in, and a keypad (or on older phones a telephone dial) to enter the telephone number of the telephone to be called. The microphone and earphone are usually built into a handset which is held up to the face to talk. The keypad may be part of the handset or of a base unit to which the handset would be connected. A landline telephone is connected by a pair of wires to the telephone network, while a mobile phone (also called a cell phone) is portable and communicates with the telephone network by radio. A cordless telephone has a portable handset which communicates by radio transmission with the handset owners base station which is connected by wire to the telephone network, and can only be used within about 50 feet from the base station.
The microphone converts the sound waves to electrical signals and then these are sent through the telephone network to the other phone and there converted by an earphone, or speaker, back into sound waves. Telephones are a duplex communications medium, meaning they allow the people on both ends to talk simultaneously. The telephone network, consisting of a worldwide net of telephone lines, fiberoptic cables, microwave transmission, cellular networks, communications satellites, and undersea telephone cables connected by switching centers, allows any telephone in the world to communicate with any other. Each telephone line has an identifying number called its telephone number. To initiate a telephone call the user enters the other telephone's number into a numeric keypad on the phone. Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include ℡ (U+2121), ☎ (U+260E), ☏ (U+260F), and ✆ (U+2706).
Although originally designed for simple voice communications, most modern telephones have many additional capabilities. They may be able to record spoken messages, send and receive text messages, take and display photographs or video, play music, and surf the Internet. A current trend is phones that integrate all mobile communication and computing needs; these are called smartphones.
Read more about Telephone: History, Basic Principles, Details of Operation, Digital Telephony, IP Telephony, Usage, Telephone Operating Companies, Patents
Famous quotes containing the word telephone:
“A woman spent all Christmas Day in a telephone box without ringing anyone. If someone comes to phone, she leaves the box, then resumes her place afterwards. No one calls her either, but from a window in the street, someone watched her all day, no doubt since they had nothing better to do. The Christmas syndrome.”
—Jean Baudrillard (b. 1929)
“It’s a hard feeling when everyone’s in a hurry to talk to somebody else, but not to talk to you. Sometimes you get a feeling of need to talk to somebody. Somebody who wants to listen to you other than “Why didn’t you get me the right number?””
—Heather Lamb, U.S. telephone operator. As quoted in Working, book 2, by Studs Terkel (1973)
“It is possible that the telephone has been responsible for more business inefficiency than any other agency except laudanum.... In the old days when you wanted to get in touch with a man you wrote a note, sprinkled it with sand, and gave it to a man on horseback. It probably was delivered within half an hour, depending on how big a lunch the horse had had. But in these busy days of rush-rush-rush, it is sometimes a week before you can catch your man on the telephone.”
—Robert Benchley (1889–1945)