The telephone (from the Greek: τῆλε, tēle, "far" and φωνή, phōnē, "voice"), often colloquially referred to as a phone, is a telecommunications device that transmits and receives sound, most commonly 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. It is one of the most common appliances in the developed world, and has long been considered indispensable to businesses, households and governments. The word "telephone" has been adapted to many languages and is widely recognized around the world.
All telephones have a microphone to speak into, an earphone 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 in older phones a telephone dial or no manual device) to enter the telephone number of the telephone being 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 or cell phone is portable and communicates with the telephone network by radio. A cordless telephone has a portable handset which communicates by radio with a base station connected by wire to the telephone network, and can only be used within a limited range of the base station
No comments:
Post a Comment