Telephone, instrument that sends and receives voice messages and data. Telephones convert speech and data to electrical energy, which is sent great distances. All telephones are linked by complex switching systems called central offices or exchanges, which establish the pathway for information to travel. Telephones are used for casual conversations, to conduct business, and to summon help in an emergency (as in the 911 service in the United States). The telephone has other uses that do not involve one person talking to another, including paying bills (the caller uses the telephone to communicate with a bank’s distant computer) and retrieving messages from an answering machine. In 2003 there were 621 main telephone lines per 1,000 people in the United States and 629 main telephone lines per 1,000 people in Canada.
About half of the information passing through telephone lines occurs entirely between special-purpose telephones, such as computers with modems. A modem converts the digital bits of a computer’s output to an audio tone, which is then converted to an electrical signal and passed over telephone lines to be decoded by a modem attached to a computer at the receiving end. Another special-purpose telephone is a facsimile machine, or fax machine, which produces a duplicate of a document at a distant point.
you can use telephone to contact important persons friends and family in different places many of the telephones today have an internet Connection.
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