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telephone,device for communicating sound, especially speech, usually by means of wires in an electric circuit. The telephones now in general use evolved from the device invented by Alexander Graham Bell and patented by him in 1876 and 1877. Although Bell is recognized as the inventor, his telephone was preceded by many attempts to produce such an instrument. The principles on which it is based, and effective model instruments, were developed by different men at so nearly the same time that there are disputes about priority. In Bell's instrument, an electric current varied in intensity and frequency in accordance with sound waves. The sound waves caused a thin plate of soft iron, called the diaphragm, to vibrate. The vibrations disturbed the magnetic field of a bar magnet placed near the diaphragm, and this disturbance induced an electric current in a wire wound about the magnet. That current, when transmitted to a distant identical instrument, caused the diaphragm in it to vibrate, reproducing the original sound. Bell's instrument was thus both transmitter and receiver. The first notable improvement of the Bell telephone differentiated the transmitting instrument from the receiving instrument. Many other inventions have improved the telephone.
The switches used to route telephone calls, which were once electromechanical, are now largely replaced by sophisticated digital electronic switching systems. The electronic switches are much more flexible because they can be programmed to provide new services. The latest generation of switches have made a number of new features possible. Users, for example, can read the telephone number of the calling party on a display device if they choose to subscribe to a "caller ID" service. In "call waiting," audio signals let a person already on a telephone know that someone else is trying to reach that person. Subscribers can also program the telephone switches to forward their calls automatically to another number ("call forwarding"). Other features include voice mailboxes and the ability to make three-way conference calls.
The problems associated with long-distance and intercity telephone service have been met with increasing success. The telephone lines used include the ordinary open wire lines, lead-sheathed cablescable,
originally wire cordage of great strength or heavy metal chain used for hauling, towing, supporting the roadway of a suspension bridge, or securing a large ship to its anchor or mooring. Today a cable often refers to a line used for the transmission of electrical signals.
..... Click the link for more information. consisting of many lines, and coaxial and fiber-optic cables. Coaxial and fiber-optic cables are typically placed underground, but other cables may be either overhead or underground. Transmission of telephone messages over long distances is often accomplished by means of radio and microwave transmissions. In some cases microwaves are sent to an orbiting communications satellite (see satellite, artificialsatellite, artificial,
object constructed by humans and placed in orbit around the earth or other celestial body (see also space probe). The satellite is lifted from the earth's surface by a rocket and, once placed in orbit, maintains its motion without further rocket propulsion.
..... Click the link for more information. ) from which they are relayed back to a distant point on the earth. Cellular telephonecellular telephone
or cellular radio,
telecommunications system in which a portable or mobile radio transmitter and receiver, or "cellphone," is linked via microwave radio frequencies to base transmitter and receiver stations that connect the user to a conventional
..... Click the link for more information. systems allow small, low-power portable radio transceivers access to the telephone network; some cellular models provide access to the Internet. The incorporation of microelectronics and digital technology has led to the inclusion of unrelated applications in telephones, such as alarm clocks, calculators, and voice memos for recording short verbal reminders. A camera phone is a cellular phone that has photo taking and sending (to another camera phone or computer) capability. Similarly, a videophone transmits and receives real-time video images.
With the advent of the InternetInternet, the,
international computer network linking together thousands of individual networks at military and government agencies, educational institutions, nonprofit organizations, industrial and financial corporations of all sizes, and commercial enterprises (called gateways
..... Click the link for more information. , computer programs have been developed that allow voice communications across long distances, bypassing conventional carriers. The programs, which often require a computer equipped with a telephone or cable modemmodem
[modulator/demodulator], an external device or internal electronic circuitry used to transmit and receive digital data over a communications line normally used for analog signals.
..... Click the link for more information. , microphone, and speakers, compress the voice message into digital signals. In other cases, a special adapter is used to allow a standard telephone to access the Internet directly though a cable modem or other broadband connection, or an Internet telephone (IP phone) may be used instead. The digital signals may be transmitted over the Internet to another computer, which must have another copy of the same program, or to a telephone. If a connection is established with another computer, the second program decompresses the digital signals and plays the sound almost instantaneously. The advantage of using the Internet is that under current tariffs no long-distance charges accrue on a computer to computer call, regardless of the length of the conversation. The disadvantages are the inferior sound quality on dialup connections and, in some cases, the need to have computers that are running the same program and the need to establish a connection between those computers.
In 1984 a federal court ordered American Telephone and Telegraph Company (AT&T) to divest its Bell Telephone operating companies (the "Baby Bells") after the court ruled that AT&T held a monopoly over U.S. telephone service. Since then, the regional operating companies and new competitors for long-distance service have grown through acquisitions and mergers. By 2007, AT&T (formerly SBC Communications, a Baby Bell, which acquired AT&T and adopted the name, and then merged in 2006 with Bell South, another Baby Bell) was the largest U.S. long-distance provider, followed by Verizon Communications (a Baby Bell that merged with MCI), and Sprint. Meanwhile, the seven Baby Bells that had been formed in 1984 were reduced to three, AT&T, Verizon, and Qwest Communications International. The distinctions between types of telephone providers, which had been created by the AT&T breakup, had disappeared, with telephone companies offering local and long-distance service in various locations, and owning wireless carriers and offering high-speed Internet service as well. At the same time these companies were also facing increasing challenges from cable televisioncable television,
the transmission of televised images to viewers by means of coaxial cables. Cable systems receive the television signal, which is sent out over cables to individual subscribers, by a common antenna (CATV) or satellite dish.
..... Click the link for more information. companies that offered Internet-based (VoIP) phone service over a broadband connection and independent VoIP companies, such as Vonage and Skype.
The primary regulator of telephone service in the United States is the Federal Communications CommissionFederal Communications Commission
(FCC), independent executive agency of the U.S. government established in 1934 to regulate interstate and foreign communications in the public interest.
..... Click the link for more information. . The International Telecommunication UnionInternational Telecommunication Union
(ITU), specialized agency of the United Nations, with headquarters at Geneva. It was created in 1934 as a result of the merging of the International Telegraph Union (est.
..... Click the link for more information. coordinates aspects of international transmissions.
See T. B. Costain, Chord of Steel: The Story of the Invention of the Telephone (1960); A. M. Noll, Introduction to Telephones and Telephone Systems (2d ed. 1991).
(1) The common name for the telephone set.
(2) In spoken Russian, the word (telefon) used for “telephone number.”
(3) Shortened form of the term “telephone communication.”
What does it mean when you dream about a telephone?
The telephone is a symbol of communication with multiple meanings. If the dreamer is not available, does not want to answer the ringing telephone, or hangs up it may indicate that communication from the unconscious is being ignored.
telephoneMeaning "distance" and "sound," a telephone is the end user terminal in a telephone or voice over IP (VoIP) network. Telephone typically refers to a desktop or wall-mounted unit, whereas portable phones are called just plain "phones" or "cordless phones," "cellphones" and "smartphones," the latter two also known as "mobile phones."
In 1876, Alexander Graham Bell's words, "Mr. Watson. Come here! I want you!" ushered in the age of telephony. See telephony, POTS, PSTN, DECT, cellphone and smartphone.
|A Century Ago|
|At the turn of the 20th century, people were "communicating over the wire" with instruments such as this Blake wall phone. (Image courtesy of Nortel Networks.)|