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A telephone is a
telecommunication Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
s device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts
sound In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' b ...
, typically and most efficiently the human voice, into electronic
signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...
s that are transmitted via
cable Cable may refer to: Mechanical * Nautical cable, an assembly of three or more ropes woven against the weave of the ropes, rendering it virtually waterproof * Wire rope, a type of rope that consists of several strands of metal wire laid into a hel ...
s and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, Alexander Graham Bell was the first to be granted a United States
patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...
for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business,
government A government is the system or group of people governing an organized community, generally a state. In the case of its broad associative definition, government normally consists of legislature, executive, and judiciary. Government is ...
, and in
household A household consists of two or more persons who live in the same dwelling. It may be of a single family or another type of person group. The household is the basic unit of analysis in many social, microeconomic and government models, and is i ...
s. The essential elements of a telephone are a
microphone A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and publ ...
(''transmitter'') to speak into and an earphone (''receiver'') which reproduces the voice at a distant location. The receiver and transmitter are usually built into a
handset A handset is a component of a telephone that a user holds to the ear and mouth to receive audio through the receiver and speak to the remote party using the built-in transmitter. In earlier telephones, the transmitter was mounted directly on ...
which is held up to the ear and mouth during conversation. The transmitter converts the sound waves to electrical signals which are sent through the telecommunication system to the receiving telephone, which converts the signals into audible sound in the receiver or sometimes a
loudspeaker A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or ...
. Telephones permit transmission in both directions simultaneously. Most telephones also contain an alerting feature, such as a ''ringer'' or a visual indicator, to announce an incoming telephone call. Telephone calls are initiated most commonly with a keypad or dial, affixed to the telephone, to enter a telephone number, which is the address of the call recipient's telephone in the telecommunication system, but other methods existed in the early history of the telephone. The first telephones were directly connected to each other from one customer's office or residence to another customer's location. Being impractical beyond just a few customers, these systems were quickly replaced by manually operated centrally located switchboards. These exchanges were soon connected together, eventually forming an automated, worldwide public switched telephone network. For greater mobility, various radio systems were developed for transmission between mobile stations on ships and automobiles in the mid-20th century. Hand-held
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
s were introduced for personal service starting in 1973. In later decades, their analog cellular system evolved into digital networks with greater capability and lower cost. Convergence in communication services has provided a broad spectrum of capabilities in cell phones, including mobile computing, giving rise to the
smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
, the dominant type of telephone in the world today.


Early history

Before the development of the electric telephone, the term ''telephone'' was applied to other inventions, and not all early researchers of the electrical device used the term. Perhaps the earliest use of the word for a communications system was the ''telephon'' created by Gottfried Huth in 1796. Huth proposed an alternative to the optical telegraph of Claude Chappe in which the operators in the signaling towers would shout to each other by means of what he called "speaking tubes", but would now be called giant
megaphone A megaphone, speaking-trumpet, bullhorn, blowhorn, or loudhailer is usually a portable or hand-held, cone-shaped acoustic horn used to amplify a person's voice or other sounds and direct it in a given direction. The sound is introduced int ...
s. A communication device for sailing vessels, called ''telephone'', was invented by Captain John Taylor in 1844. This instrument used four
air horn An air horn is a pneumatic device designed to create an extremely loud noise for signaling purposes. It usually consists of a source which produces compressed air, which passes into a horn through a reed or diaphragm. The stream of air cause ...
s to communicate with vessels in foggy weather.
Johann Philipp Reis Johann Philipp Reis (; 7 January 1834 – 14 January 1874) was a self-taught German scientist and inventor. In 1861, he constructed the first ''make-and-break'' telephone, today called the Reis telephone. Early life and education Reis ...
used the term in reference to his invention, commonly known as the Reis telephone, in c. 1860. His device appears to be the first device based on the conversion of sound into electrical impulses. The term ''telephone'' was adopted into the vocabulary of many languages. It is derived from the el, τῆλε, ''tēle'', "far" and φωνή, ''phōnē'', "voice", together meaning "distant voice". Credit for the invention of the electric telephone is frequently disputed. As with other influential inventions such as
radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...
,
television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...
, the light bulb, and the computer, several inventors pioneered experimental work on ''voice transmission over a wire'' and improved on each other's ideas. New controversies over the issue still arise from time to time. Charles Bourseul,
Antonio Meucci Antonio Santi Giuseppe Meucci ( , ; 13 April 1808 – 18 October 1889) was an Italian inventor and an associate of Giuseppe Garibaldi, a major political figure in the history of Italy.
,
Johann Philipp Reis Johann Philipp Reis (; 7 January 1834 – 14 January 1874) was a self-taught German scientist and inventor. In 1861, he constructed the first ''make-and-break'' telephone, today called the Reis telephone. Early life and education Reis ...
, Alexander Graham Bell, and Elisha Gray, amongst others, have all been credited with the invention of the telephone. Alexander Graham Bell was the first to be awarded a patent for the electric telephone by the United States Patent and Trademark Office (USPTO) in March 1876. Before Bell's patent, the telephone transmitted sound in a way that was similar to the telegraph. This method used vibrations and circuits to send electrical pulses, but was missing key features. Bell found that this method produced a sound through intermittent currents, but in order for the telephone to work a fluctuating current reproduced sounds the best. The fluctuating currents became the basis for the working telephone, creating Bell's patent. That first patent by Bell was the ''master patent'' of the telephone, from which other patents for electric telephone devices and features flowed. In 1876, shortly after Bell's patent application, Hungarian engineer Tivadar Puskás proposed the telephone switch, which allowed for the formation of telephone exchanges, and eventually networks. In the United Kingdom, ''the blower'' is used as a slang term for a telephone. The term came from navy slang for a
speaking tube A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance. Use of pipes was suggested by Francis Bacon in the ''New Atlantis'' (1672). The usage for tel ...
. In the U.S., a somewhat dated slang term refers to the telephone as "the horn," as in "I couldn't get him on the horn," or "I'll be off the horn in a moment."


Timeline of early development

* 1844:
Innocenzo Manzetti Innocenzo Vincenzo Bartolomeo Luigi Carlo Manzetti (; 17 March 1826 – 15 March 1877) was an Italians, Italian inventor born in Aosta. Following his primary school studies he went to the Jesuit-run Saint Bénin Boarding School and then on to ...
first mooted the idea of a "speaking telegraph" or telephone. Use of the "speaking telegraph" and "sound telegraph" monikers would eventually be replaced by the newer, distinct name, "telephone". * 26 August 1854: Charles Bourseul published an article in the magazine '' L'Illustration'' (Paris): "Transmission électrique de la parole" (electric transmission of speech), describing a "make-and-break" type telephone transmitter later created by Johann Reis. * 26 October 1861:
Johann Philipp Reis Johann Philipp Reis (; 7 January 1834 – 14 January 1874) was a self-taught German scientist and inventor. In 1861, he constructed the first ''make-and-break'' telephone, today called the Reis telephone. Early life and education Reis ...
(1834–1874) publicly demonstrated the Reis telephone before the Physical Society of Frankfurt. Reis's telephone was not limited to musical sounds. Reis also used his telephone to transmit the phrase "Das Pferd frisst keinen Gurkensalat" ("The horse does not eat cucumber salad"). * 22 August 1865, ''La Feuille d'Aoste'' reported "It is rumored that English technicians to whom Manzetti illustrated his method for transmitting spoken words on the telegraph wire intend to apply said invention in England on several private telegraph lines". However, telephones would not be demonstrated there until 1876, with a set of telephones from Bell. * 28 December 1871:
Antonio Meucci Antonio Santi Giuseppe Meucci ( , ; 13 April 1808 – 18 October 1889) was an Italian inventor and an associate of Giuseppe Garibaldi, a major political figure in the history of Italy.
files patent caveat No. 3335 in the U.S. Patent Office, titled "Sound Telegraph", describing communication of voice between two people by wire. A patent caveat was not an invention
patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...
award, but only an unverified notice filed by an individual that he or she intends to file a patent application in the future. * 1874: Meucci, after having renewed the caveat for two years does not renew it again, and the caveat lapses. * 6 April 1875: Bell's U.S. Patent 161,739 "Transmitters and Receivers for Electric Telegraphs" is granted. This uses multiple vibrating steel reeds in make-break circuits. * 11 February 1876: Elisha Gray invents a liquid transmitter for use with the telephone but does not build one. * 14 February 1876: Gray files a patent caveat for transmitting the human voice through a telegraphic circuit. * 14 February 1876: Alexander Graham Bell applies for the patent "Improvements in Telegraphy", for electromagnetic telephones using what is now called amplitude modulation (oscillating current and voltage) but which he referred to as "undulating current". * 19 February 1876: Gray is notified by the U.S. Patent Office of an interference between his caveat and Bell's patent application. Gray decides to abandon his caveat. * 7 March 1876: Bell's U.S. patent 174,465 "Improvement in Telegraphy" is granted, covering "the method of, and apparatus for, transmitting vocal or other sounds telegraphically…by causing electrical undulations, similar in form to the vibrations of the air accompanying the said vocal or other sound." * 10 March 1876: The first successful telephone transmission of clear speech using a liquid transmitter when Bell spoke into his device, "Mr. Watson, come here, I want to see you." and Watson heard each word distinctly. * 30 January 1877: Bell's U.S. patent 186,787 is granted for an electromagnetic telephone using permanent magnets, iron diaphragms, and a call bell. * 27 April 1877:
Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventi ...
files a patent application for a carbon (graphite) transmitter. It was published as No. 474,230 on 3 May 1892, after a 15-year delay because of litigation. Edison was granted patent 222,390 for a carbon granules transmitter in 1879.


Early commercial instruments

Early telephones were technically diverse. Some used a water microphone, some had a metal diaphragm that induced current in an electromagnet wound around a permanent magnet, and some were dynamic – their diaphragm vibrated a coil of wire in the field of a permanent magnet or the coil vibrated the diaphragm. The sound-powered dynamic variants survived in small numbers through the 20th century in military and maritime applications, where its ability to create its own electrical power was crucial. Most, however, used the Edison/Berliner carbon transmitter, which was much louder than the other kinds, even though it required an induction coil which was an
impedance matching In electronics, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or minimize si ...
transformer to make it compatible with the impedance of the line. The Edison patents kept the Bell monopoly viable into the 20th century, by which time the network was more important than the instrument. Early telephones were locally powered, using either a dynamic transmitter or by the powering of a transmitter with a local battery. One of the jobs of outside plant personnel was to visit each telephone periodically to inspect the battery. During the 20th century, telephones powered from the telephone exchange over the same wires that carried the voice signals became common. Early telephones used a single wire for the subscriber's line, with ground return used to complete the circuit (as used in telegraphs). The earliest dynamic telephones also had only one port opening for sound, with the user alternately listening and speaking (or rather, shouting) into the same hole. Sometimes the instruments were operated in pairs at each end, making conversation more convenient but also more expensive. At first, the benefits of a telephone exchange were not exploited. Instead, telephones were leased in pairs to a subscriber, who had to arrange for a telegraph contractor to construct a line between them, for example, between a home and a shop. Users who wanted the ability to speak to several different locations would need to obtain and set up three or four pairs of telephones. Western Union, already using telegraph exchanges, quickly extended the principle to its telephones in
New York City New York, often called New York City or NYC, is the most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the most densely populated major city in the Un ...
and
San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...
, and Bell was not slow in appreciating the potential.
Signalling In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
began in an appropriately primitive manner. The user alerted the other end, or the exchange operator, by
whistling Whistling without the use of an artificial whistle is achieved by creating a small opening with one's lips, usually after applying moisture (licking one's lips or placing water upon them) and then blowing or sucking air through the space. The a ...
into the transmitter. Exchange operation soon resulted in telephones being equipped with a bell in a ringer box, first operated over a second wire, and later over the same wire, but with a condenser (
capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of ...
) in series with the bell coil to allow the AC ringer signal through while still blocking DC (keeping the phone "
on hook In telephony, on-hook and off-hook are two states of a communication circuit. On subscriber telephones the states are produced by placing the handset onto or off the hookswitch. Placing the circuit into the off-hook state is also called ''seizing th ...
"). Telephones connected to the earliest
Strowger switch The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Because of it ...
automatic exchanges had seven wires, one for the knife switch, one for each telegraph key, one for the bell, one for the push-button and two for speaking. Large wall telephones in the early 20th century usually incorporated the bell, and separate bell boxes for desk phones dwindled away in the middle of the century. Rural and other telephones that were not on a common battery exchange had a
magneto A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, ...
hand-cranked generator to produce a high voltage alternating signal to ring the bells of other telephones on the line and to alert the operator. Some local farming communities that were not connected to the main networks set up barbed wire telephone lines that exploited the existing system of field fences to transmit the signal. In the 1890s a new smaller style of telephone was introduced, packaged in three parts. The transmitter stood on a stand, known as a " candlestick" for its shape. When not in use, the receiver hung on a hook with a switch in it, known as a "switchhook". Previous telephones required the user to operate a separate switch to connect either the voice or the bell. With the new kind, the user was less likely to leave the phone "off the hook". In phones connected to magneto exchanges, the bell, induction coil, battery and magneto were in a separate bell box or " ringer box". In phones connected to common battery exchanges, the ringer box was installed under a desk, or other out-of-the-way place, since it did not need a battery or magneto. Cradle designs were also used at this time, having a handle with the receiver and transmitter attached, now called a
handset A handset is a component of a telephone that a user holds to the ear and mouth to receive audio through the receiver and speak to the remote party using the built-in transmitter. In earlier telephones, the transmitter was mounted directly on ...
, separate from the cradle base that housed the magneto crank and other parts. They were larger than the "candlestick" and more popular. Disadvantages of single-wire operation such as crosstalk and hum from nearby AC power wires had already led to the use of twisted pairs and, for long-distance telephones,
four-wire circuit In telecommunication, a four-wire circuit is a two-way circuit using two paths so arranged that the respective signals are transmitted in one direction only by one path and in the other direction by the other path. The four-wire circuit gets its ...
s. Users at the beginning of the 20th century did not place long-distance calls from their own telephones but made an appointment and were connected with the assistance of a telephone operator. What turned out to be the most popular and longest-lasting physical style of telephone was introduced in the early 20th century, including Bell's 202-type desk set. A carbon granule transmitter and electromagnetic receiver were united in a single molded plastic handle, which when not in use was secured in a cradle in the base unit. The circuit diagram of the model 202 shows the direct connection of the transmitter to the line, while the receiver was inductively coupled. In local battery configurations, when the local loop was too long to provide sufficient current from the exchange, the transmitter was powered by a local battery and inductively coupled, while the receiver was included in the local loop. The coupling transformer and the ringer were mounted in a separate enclosure, called the subscriber set. The dial switch in the base interrupted the line current by repeatedly but very briefly disconnecting the line one to ten times for each digit, and the hook switch (in the center of the circuit diagram) disconnected the line and the transmitter battery while the handset was on the cradle. In the 1930s, telephone sets were developed that combined the bell and induction coil with the desk set, obviating a separate ringer box. The rotary dial becoming commonplace in the 1930s in many areas enabled customer-dialed service, but some magneto systems remained even into the 1960s. After World War II, the telephone networks saw rapid expansion and more efficient telephone sets, such as the
model 500 telephone The Western Electric model 500 telephone series was the standard domestic desk telephone set issued by the Bell System in North America from 1950 through the 1984 Bell System divestiture. Millions of model 500-series phones were produced and were ...
in the United States, were developed that permitted larger local networks centered around central offices. A breakthrough new technology was the introduction of Touch-Tone signaling using
push-button telephone The push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to having a rotary dial as in earlier telephone instruments. Western Electric experimented as early as 1941 with methods of using mech ...
s by American Telephone & Telegraph Company (AT&T) in 1963. File:Ericsson bakelittelefon 1931 sv.jpg, Ericsson DBH 1001 (ca. 1931), the first combined telephone made with a Bakelite housing and handset. File:Minalinpampangajf2520 02.JPG, Telephone used by American soldiers (WWII,
Minalin, Pampanga Minalin, officially the Municipality of Minalin ( pam, Balen ning Minalin; fil, Bayan ng Minalin), is a 4th class municipality in the province of Pampanga, Philippines. According to the 2020 census, it has a population of 48,380 people. Original ...
,
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...
) File:Oldphone.ogv, Video shows the operation of an Ericofon File:Sound-Powered Telephone Systems.jpg, Modern sound-powered emergency telephone File:Motorola L71 on the China Mobile network 20100521.jpg, One type of
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
, called a cell phone


Digital telephones and voice over IP

The invention of the
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
in 1947 dramatically changed the technology used in telephone systems and in the long-distance transmission networks, over the next several decades. With the development of stored program control and
MOS integrated circuit upright=1.6, gate (G), body (B), source (S), and drain (D) terminals. The gate is separated from the body by an gate oxide">insulating layer (pink). The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also ...
s for electronic switching systems, and new transmission technologies such as
pulse-code modulation Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM Stream (comp ...
(PCM),
telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
gradually evolved towards
digital telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
, which improved the capacity, quality, and cost of the network. Integrated Services Digital Network (ISDN) was launched in the 1980's, providing businesses and consumers with access to digital telephony services such as data, voice,
video Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syst ...
, and
fax Fax (short for facsimile), sometimes called telecopying or telefax (the latter short for telefacsimile), is the telephonic transmission of scanned printed material (both text and images), normally to a telephone number connected to a printer o ...
services. The development of digital data communications methods made it possible to digitize voice and transmit it as real-time data across
computer network A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...
s and the
Internet The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
, giving rise to the field of Internet Protocol (IP) telephony, also known as
voice over Internet Protocol Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...
(VoIP). VoIP has proven to be a disruptive technology that is rapidly replacing traditional telephone network infrastructure. By January 2005, up to 10% of telephone subscribers in Japan and
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...
had switched to this digital telephone service. A January 2005
Newsweek ''Newsweek'' is an American weekly online news magazine co-owned 50 percent each by Dev Pragad, its president and CEO, and Johnathan Davis, who has no operational role at ''Newsweek''. Founded as a weekly print magazine in 1933, it was widely ...
article suggested that Internet telephony may be "the next big thing." The technology has spawned a new industry comprising many VoIP companies that offer services to
consumer A consumer is a person or a group who intends to order, or uses purchased goods, products, or services primarily for personal, social, family, household and similar needs, who is not directly related to entrepreneurial or business activities. ...
s and businesses. The reported global VoIP market in October 2021 was $85.2 billion with a projection of $102.5 billion by 2026. IP telephony uses high-bandwidth Internet connections and specialized customer premises equipment to transmit telephone calls via the Internet, or any modern private data network. The customer equipment may be an analog telephone adapter (ATA) which translates the signals of a conventional analog telephone; an IP Phone, a dedicated standalone device; or a computer
softphone A softphone is a software program for making telephone calls over the Internet using a general purpose computer rather than dedicated hardware. The softphone can be installed on a piece of equipment such as a desktop, mobile device, or other comp ...
application, utilizing the microphone and headset devices of a personal computer or smartphone. While traditional analog telephones are typically powered from the central office through the telephone line, digital telephones require a local power supply. Internet-based digital service also requires special provisions to provide the service location to the emergency services when an
emergency telephone number Most public switched telephone networks have a single emergency telephone number (sometimes known as the universal emergency telephone number or the emergency services number) that allows a caller to contact local emergency services for assis ...
is called.


Cordless telephones

A
cordless telephone A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same building or within some short ...
or portable telephone consists of a base station unit and one or more portable cordless
handset A handset is a component of a telephone that a user holds to the ear and mouth to receive audio through the receiver and speak to the remote party using the built-in transmitter. In earlier telephones, the transmitter was mounted directly on ...
s. The base station connects to a telephone line, or provides service by voice over IP (VOIP). The handset communicates with the base station via
radio frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the ...
signals. A handset's operational range is limited, usually to within the same building or within a short distance from the base station.


Base station

Base stations include a radio transceiver which enables full-duplex, outgoing and incoming signals and speech with the handsets. The base station often includes a microphone, audio amplifier, and a loudspeaker to enable hands-free
speakerphone A speakerphone is a telephone with a microphone and loudspeaker provided separately from those in the handset. This device allows multiple persons to participate in a conversation. The loudspeaker broadcasts the voice or voices of those on the ot ...
conversations, without needing to use a handset. The base station may also have a numeric keypad for dialing, and a display for
caller ID Caller identification (Caller ID) is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call i ...
. In addition, answering machine function may be built in. The cordless handset contains a rechargeable battery, which the base station recharges when the handset rests in its cradle. Muilt-handset systems generally also have additional charging stands. A cordless telephone typically requires a constant
electricity supply Mains electricity or utility power, power grid, domestic power, and wall power, or in some parts of Canada as hydro, is a general-purpose alternating-current (AC) electric power supply. It is the form of electrical power that is delivered to h ...
to power the base station and charger units by means of a DC transformer which plugs into a wall AC power outlet.


Mobile phones

A typical SIM card (mini-SIM with a cutout to convert the card to micro-SIM size) A
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
or cellphone or hand phone is a handheld telephone which connects via radio transmissions to a cellular telephone network. The cellular network consists of a network of ground based transmitter/receiver stations with antennas – which are usually located on towers or on buildings – and infrastructure connecting to land-based telephone lines. Analog cellular networks first appeared in 1979, with the first digital cellular networks appearing in the early 1990s. Mobile phones require a
SIM card A typical SIM card (mini-SIM with micro-SIM cutout) A GSM mobile phone file:Simkarte NFC SecureElement.jpg, T-Mobile nano-SIM card with NFC capabilities in the SIM tray of an iPhone 6s file:Tf sim both sides.png, A TracFone Wireless SIM card ha ...
to be inserted into the phone. The SIM card is a small PVC card containing a small integrated circuit which stores the user's
international mobile subscriber identity The international mobile subscriber identity (IMSI) is a number that uniquely identifies every user of a cellular network. It is stored as a field and is sent by the mobile device to the network. It is also used for acquiring other details of th ...
(IMSI) number and its related key, which are used to identify and authenticate subscribers to the cellular network. Mobile phones generally incorporate an LCD or
OLED An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light i ...
display, with some types, such as smartphones, having touch screens. Since the 1990s, mobile phones have gained other features which are not directly related to their primary function as telephones. These include text messaging, calendars, alarm clocks, personal schedulers, cameras, music players, games and later, internet access and
smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
functionality. Nearly all mobile phones have the ability to send text messages to other users via the SMS (Short Message Service) protocol. The multimedia messaging service (MMS) protocol enables users to send and receive multimedia content, such as photos, audio files and video files. As their functionality has increased over the years, many types of mobile phone, notably smartphones, require an
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...
to run. Popular mobile phone operating systems in the past have included Symbian,
Palm OS Palm OS (also known as Garnet OS) was a mobile operating system initially developed by Palm, Inc., for personal digital assistants (PDAs) in 1996. Palm OS was designed for ease of use with a touchscreen-based graphical user interface. It is pro ...
,
BlackBerry OS BlackBerry OS is a discontinued proprietary mobile operating system developed by Canadian company BlackBerry Limited for its BlackBerry line of smartphone handheld devices. The operating system provides multitasking and supports specialized i ...
and mobile phone versions of Windows. As of 2022, the most used operating systems are Google's Android and Apple's
iOS iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also include ...
. Before the era of smartphones, mobile phones were generally manufactured by companies specializing in telecommunications equipment, such as
Nokia Nokia Corporation (natively Nokia Oyj, referred to as Nokia) is a Finnish multinational telecommunications, information technology, and consumer electronics corporation, established in 1865. Nokia's main headquarters are in Espoo, Finland, i ...
,
Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorol ...
, and Ericsson. Since the advent of smartphones, mobile phone manufacturers have also included consumer electronics companies, such as
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...
,
Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
and Xiaomi.


Smartphones

As of 2022, most mobile phones are smartphones, being a combination of a mobile phone and a personal computing device in the same unit. Most smartphones are primarily operated using a
graphical user interface The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inst ...
and a touch screen. Many phones have a secondary voice user interface, such as
Siri Siri ( ) is a virtual assistant that is part of Apple Inc.'s iOS, iPadOS, watchOS, macOS, tvOS, and audioOS operating systems. It uses voice queries, gesture based control, focus-tracking and a natural-language user interface to answer qu ...
on Apple iPhones, which can operate many of the device's functions, as well as enabling users to use spoken commands to interact with the internet. Typically alphanumeric text input is accomplished via an on-screen virtual keyboard, although some smartphones have a small physical keyboard. Smartphones offer the ability to access internet data through the cellular network and via wi-fi, and usually allow direct connectivity to other devices via Bluetooth or a wired interface, such as USB or
Lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
connectors. Smartphones, being able to run apps, have vastly expanded functionality compared to previous mobile phones. Having internet access and built in cameras, smartphones have made video calling readily accessible via IP connections. Smartphones also have access to a large number of web services and web apps, giving them functionality similar to traditional computers, although smartphones are often limited by their relatively small screen size and the size of their keyboards. Typically, smartphones feature such tools as cameras, media players, web browsers, email clients, interactive maps, satellite navigation and a variety of sensors, such as a
compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...
,
accelerometers An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acce ...
and
GPS receivers A satellite navigation device (satnav device) is a user equipment that uses one or more of several global navigation satellite systems (GNSS) to calculate the device's geographical position and provide navigational advice. Depending on the ...
. In addition to voice calls, smartphone users commonly communicate using a wide variety of messaging formats, including SMS, MMS, email, and various proprietary messaging services, such as
iMessage iMessage is an instant messaging service developed by Apple Inc. and launched in 2011. iMessage functions exclusively on Apple platforms: macOS, iOS, iPadOS, and watchOS. Core features of iMessage, available on all supported platforms, in ...
and various social media platforms.


Mobile phone usage

In 2002, only 10% of the world's population used
mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...
s and by 2005 that percentage had risen to 46%. By the end of 2009, there were a total of nearly 6 billion mobile and fixed-line telephone subscribers worldwide. This included 1.26 billion fixed-line subscribers and 4.6 billion mobile subscribers.Next-Generation Networks Set to Transform Communications
International Telecommunication Union website, 4 September 2007. Retrieved 5 July 2009.


See also

* Bell System *
Bell Telephone Memorial The Bell Memorial (also known as the Bell Monument or Telephone Monument) is a memorial designed by Walter Seymour Allward to commemorate the invention of the telephone by Alexander Graham Bell at the Bell Homestead National Historic Site, in Bra ...
* Cellular network *
Cordless telephone A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same building or within some short ...
* Harvard sentences *
Index of telephone-related articles {{wiktionarypar, telephone These are some of the links to articles that are telephone related. See Telephony for many more links 0-9 * Harmonised service of social value, 116 telephone number * Toll-free telephone number, 800 number A-F * Alexand ...
* Jipp curve *
List of telephone operating companies This list identifies the fixed line operators and the mobile operators for the top 200 most populous countries in the world. The list of countries and their populations is from List of countries by population. The CIA World Factbook is cited ...
*
Mobile operating system A mobile operating system is an operating system for mobile phones, tablets, smartwatches, smartglasses, or other non-laptop personal mobile computing devices. While computers such as typical laptops are "mobile", the operating systems used on ...
* Multimedia messaging service (MMS) *
Party line (telephony) A party line (multiparty line, shared service line, party wire) is a local loop telephone circuit that is shared by multiple telephone service subscribers. Party line systems were widely used to provide telephone service, starting with the fir ...
*
Phone hacking Phone hacking is the practice of exploring a mobile device often using computer exploits to analyze everything from the lowest memory and central processing unit levels up to the highest file system and process levels. Modern open source toolin ...
* Radiotelephone * Satellite phone *
SIM card A typical SIM card (mini-SIM with micro-SIM cutout) A GSM mobile phone file:Simkarte NFC SecureElement.jpg, T-Mobile nano-SIM card with NFC capabilities in the SIM tray of an iPhone 6s file:Tf sim both sides.png, A TracFone Wireless SIM card ha ...
* Spamming * Telephone keypad *
Telephone jack and plug A telephone jack and a telephone plug are electrical connectors for connecting a telephone set or other telecommunications apparatus to the telephone wiring inside a building, establishing a connection to a telephone network. The plug is inserted ...
* Telephone tapping *
Tip and ring Tip and ring are the two conductors or sides of a telephone line. Their names are derived from the telephone plugs used for connecting telephone calls in manual switchboards. One side of the line is connected to the metal ''tip'' of the plug, and ...
* Videophone


References


Further reading

* Brooks, John (1976). ''Telephone: The first hundred years''. HarperCollins. * * Casson, Herbert Newton. (1910) ''The history of the telephone'
online
* Coe, Lewis (1995). ''The Telephone and Its Several Inventors: A History.'' Jefferson, NC: McFarland & Co. * Evenson, A. Edward (2000). ''The Telephone Patent Conspiracy of 1876: The Elisha Gray – Alexander Bell Controversy.'' Jefferson, NC: McFarland & Co. * Fischer, Claude S. (1994) ''America calling: A social history of the telephone to 1940'' (Univ of California Press, 1994) * Huurdeman, Anton A. (2003). ''The Worldwide History of Telecommunications'' Hoboken: NJ: Wiley-IEEE Press. * John, Richard R. (2010). ''Network Nation: Inventing American Telecommunications.'' Cambridge, MA: Harvard University Press. * MacDougall, Robert. ''The People's Network: The Political Economy of the Telephone in the Gilded Age.'' Philadelphia: University of Pennsylvania Press. * Mueller, Milton. (1993) "Universal service in telephone history: A reconstruction." ''Telecommunications Policy'' 17.5 (1993): 352–69. * Todd, Kenneth P. (1998)
''A Capsule History of the Bell System''
American Telephone & Telegraph Company (AT&T).


External links



* *
Virtual museum of early telephones


* * * * * * —''Telegraphy'' (Bell's first telephone patent)—Alexander Graham Bell
US 186,787
��''Electric Telegraphy'' (permanent magnet receiver)—Alexander Graham Bell
US 474,230
��''Speaking Telegraph'' (graphite transmitter)—Thomas Edison
US 203,016
��''Speaking Telephone'' (carbon button transmitter)—Thomas Edison
US 222,390
��''Carbon Telephone'' (carbon granules transmitter)—Thomas Edison
US 485,311
��''Telephone'' (solid back carbon transmitter)—Anthony C. White (Bell engineer) This design was used until 1925 and installed phones were used until the 1940s.
US 3,449,750
��''Duplex Radio Communication and Signalling Apparatus''—G. H. Sweigert
US 3,663,762
��''Cellular Mobile Communication System''—Amos Edward Joel (Bell Labs)
US 3,906,166
��''Radio Telephone System'' (DynaTAC cell phone)—Martin Cooper et al. (Motorola) {{Authority control 1876 introductions American inventions Canadian inventions Discovery and invention controversies German inventions Scottish inventions Office equipment Telecommunications equipment Articles containing video clips Home appliances 19th-century inventions