Telephone, mobile phone
, Telephone card
, Telephone switchboard
, Telephone exchange
, Telephone number
, Telephone company
, 610 (telephone)
, Telephone tapping
, rotary dial
is a telecommunication
s device which is used to transmit
and receive sound
(most commonly voice
and speech) across distance. Most telephones operate through transmission of electric signals
over a complex telephone network
which allows almost any phone user to communicate with almost any other.
An elementary telephone system consists of three elements:
* For each subscriber, the system must contain the equipment necessary to convert sound to electrical signals and back. This allows the subscriber to answer or initiate a call.
* The system must contain a central switching facility which interconnects all the subscribers.
* Finally, the system requires wiring or other means to connect the subscribers to the central switching facility.
There are three principal ways a subscriber may be connected to the telephone network:
* Historically, and still very commonly, by dedicated physical wire connections run in overhead or underground cables;
* By radio, as in a cordless, cellular, satellite or radiotelephone and
* By voice over internet protocol
(VoIP) telephones, which use broadband internet
The identity of the inventor of the electric telephone remains in dispute. Antonio Meucci
, Johann Philipp Reis
, Alexander Graham Bell
and Elisha Gray
, amongst others, have all been credited with the invention
The very early history of the telephone is a confusing morass of claim and counterclaim, which was not clarified by the huge mass of lawsuits which hoped to resolve the patent claims of individuals. Much money was expended, particularly in the Bell Telephone
companies, and the aggressive defense of the Bell patents resulted in much confusion. Additionally, the earliest investigators preferred publication in the popular press and demonstration to investors instead of scientific publication and demonstration to fellow scientists. It is important to note that there is probably no single "inventor of the telephone". The modern telephone is the result of work done by many hands, all worthy of recognition of their addition to the field. Only in the last ten years, however, has the British
government announced that it now recognizes (primarily for educational purposes) Antonio Meucci
(see below) as the 'first inventor' of the This was acknowledged even by the US Congress in 2003 http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=108_cong_bills&docid=f:sr223is.txt.pdf
see|Timeline of the
see|Invention of the
The following is a brief summary of the history of the invention of the telephone:
*1849 Antonio Meucci
demonstrates a device he later called a telephone to individuals in Havana. (The demonstration involves direct electrical connections to people.)
*1854 Charles Bourseul
publishes a description of a make-break telephone transmitter and receiver but does not construct a working instrument.
Meucci demonstrates an electric telephone in New York. http://chem.ch.huji.ac.il/~eugeniik/history/meucci.html
*1860 Johann Philipp Reis
demonstrates a "telephon" using a pressure contact transmitter after the make-break design of Bourseul and a knitting needle receiver. Witnesses said they heard human voices being transmitted.
Meucci demonstrates his telephone on Staten Island.
Reis manages to transfer voice electrically over a distance of 340 feet, see Reis' telephone
In an attempt to give his musical automaton a voice, Innocenzo Manzetti
invents the 'Speaking telegraph'. He shows no interest in patenting his device, but it is reported in newspapers.
Meucci reads of Manzetti's invention and writes to the editors of two newspapers claiming priority and quoting his first experiment in 1849. He writes "I do not wish to deny Mr. Manzetti his invention, I only wish to observe that two thoughts could be found to contain the same discovery, and that by uniting the two ideas one can more easily reach the certainty about a thing this important." If he reads Meucci's offer of collaboration, Manzetti does not respond.
Meucci files a patent caveat
(a statement of intention to patent).
*1872 Elisha Gray
founds Western Electric
*1872 Prof Vanderwyde demonstrated Reis's telephone in New York.
*July 1873 Thomas Edison
notes variable resistance in carbon grains due to pressure and builds a rheostat
based on the principle.
*May 1874 Gray invents electromagnet device for transmitting musical tones. Some of his receivers use steel diaphragms.
*December 29, 1874 Gray demonstrates his musical tones device and transmitted "familiar melodies through telegraph wire" at the Presbyterian Church in Highland Park, Illinois.
*2 June 1875 Alexander Graham Bell
transmits the sound of plucked steel reeds using electromagnet instruments.
*1 July 1875
Bell uses a bi-directional "gallows" telephone that was able to transmit "indistinct but voicelike sounds" but not clear speech. Both the transmitter and the receiver were identical membrane electromagnet instruments.
*1875 Thomas Edison
experiments with acoustic telegraphy
and in November builds an electro-dynamic receiver but does not exploit it.
*11 February 1876
Elisha Gray invents a liquid transmitter for use with a telephone, but does not build one.
*14 February 1876
(about 9:30 am) Gray or his lawyer brings to the Patent Office Gray's caveat for the telephone. (A caveat was a notice of intention to file a patent application)
*14 February 1876
(about 11:30am) Bell's lawyer brings to the Patent Office Bell's patent application for the telephone. Bell's lawyer requested that it be registered immediately in the cash blotter.
**About two hours later Elisha Gray's caveat was registered in the cash blotter. Although Gray could have converted his caveat into a patent application, he did not do so.
*7 March 1876
Bell's US patent 174,465 for the telephone is granted.
*10 March 1876
Bell transmits speech "Mr. Watson, come here, I want to see you." using a liquid transmitter and an electromagnetic receiver. Spilling battery acid was not recorded in his lab notes.
*16 May 1876 Thomas Edison
files first patent application for acoustic telegraphy
*20 January 1877
Edison "first succeeded in transmitting over wires many articulated sentences" using carbon granules as a pressure sensitive variable resistance under the pressure of a diaphragm (Josephson, p143).
*30 January 1877
Bell's US patent 186,787 is granted for an electro-magnetic telephone using permanent magnets, iron diaphragms, and a call bell.
*4 March 1877 Emile Berliner
invents a microphone
based on the "loose contact" between two metal electrodes, an improvement on the Reis telephone, and in April 1877 files a caveat of an invention in process.
* 27 April 1877
Edison files for a patent on a carbon (graphite) transmitter. The patent 474,230 was granted May 3, 1892 after a 15 year delay due to litigation. In 1892 a federal court ruled Edison and not Berliner was the inventor of the carbon transmitter. Edison was granted patent 222,390 for a carbon granules transmitter in 1879. Edison's carbon granules transmitter and Bell's electromagnetic receiver were used, with improvements, by the Bell system for many decades thereafter (Josephson, p 146).
Later historythumb|right|The [Ericofon
was a very futuristic handset when it was introduced in 1956.]
The history of additional inventions and improvements of the electrical telephone includes the carbon microphone
(later replaced by the electret
microphone now used in almost all telephone transmitters), the manual switchboard
, the rotary dial
, the automatic telephone exchange
, the computerized telephone switch
, Touch Tone® dialing
), and the digitization of sound using different coding techniques including pulse code modulation or PCM
(which is also used for .WAV
, .AIF files and compact discs).
Newer systems include IP telephony
, mobile cellular phone
telephones, and the third generation cell phone
systems that promise to include high-speed packet data
The industry has divided into telephone equipment manufacturers and telephone network operators (telcos). Operating companies often hold a national monopoly
. In the United States, the Bell System
was vertically integrated. It fully or partially owned the telephone companies that provided service to about 80% of the telephones in the country and also owned Western Electric
, which manufactured or purchased virtually all the equipment and supplies used by the local telephone companies. The Bell System divested itself of the local telephone companies in 1984 in order to settle an antitrust
suit brought against it by the United States Department of Justice
In 1926 Bell Labs and the British Post Office engineered the first two-way conversation across the Atlantic.
The first commercial transatlantic telephone call was between New York City
and occurred on January 7
The Public Switched Telephone Network
(PSTN) has gradually evolved towards digital telephony which has improved the capacity and quality of the network. End-to-end analog
telephone networks were first modified in the 1970s by upgrading long-haul transmission networks with SONET
technology and fiber optic
transmission methods. Digital transmission made it possible to carry multiple digitized switched circuit
s on a single transmission medium (known as multiplexing
). While today the end instrument remains analog, the analog signals reaching the aggregation point (Serving Area Interface
(SAI) or the central office
(CO) ) are typically converted to digital signals
. Digital loop carrier
s (DLC) are often used, placing the digital network ever closer to the customer premises, relegating the analog local loop
to legacy status.
Wireless phone systems
While the term "wireless
" means radio
and can refer to any telephone that uses radio waves (such telephones have existed since 1915: see
"Hello, Hawaii, How Are You?
"), it is primarily used for cell phone
s. In the United States
wireless companies tend to use the term wireless to refer to a wide range of services while the cell phone itself is called a mobile phone, mobile, PCS phone
, cell phone or simply cell with the trend now moving towards mobile
The changes in terminology is partially due to providers using different terms in marketing
to differentiate newer digital services from older analog systems and services of one company from another.
Cordless telephoneright|thumb|125px|Cordless handsetCordless telephone
s, invented by Teri Pall in 1965, consist of a base unit that connects to the land-line system and also communicates with remote handset
s by low power radio
. This permits use of the handset from any location within range of the base. Because of the power required to transmit to the handset, the base station is powered with an electronic power supply
. Thus, cordless phones typically do not function during power outages. Initially, cordless phones used the 1.7 MHz frequency range to communicate between base and handset. Because of quality and range problems, these units were soon superseded by systems that used frequency modulation
(FM) at higher frequency ranges (49 MHz, 900 MHz, 2.4 GHz, and 5.8 GHz). The 2.4 GHz cordless phones can interfere with certain wireless LAN
) due to the usage of the same frequencies. On the 2.4 GHz band, several "channels" are utilized in an attempt to guard against degradation in the quality of the voice signal due to crowding. The range of modern cordless phones is normally on the order of a few hundred meters
Most modern mobile phone systems are cell-structured. Radio
is used to communicate between a handset and nearby cell site
When a handset gets too far from a cell site, a computer system commands the handset and a closer cell site to take up the communications on a different channel without interrupting the call.
Radio frequencies are a limited, shared resource. The higher frequencies used by cell phones have advantages over short distances. Connection distance is somewhat predictable and can be controlled by adjusting the power level. By only using enough power to connect to the "nearest" cell site phones using one cell site will cause almost no interference with phones using the same frequencies on another cell site. The higher frequencies also work well with various forms of multiplexing
which allows more than one phone to connect to the same tower with the same set of frequencies.
Some mobile telephones, especially those used in remote locations, where constructing a cell network
would be too unprofitable or difficult, instead communicate directly with an orbiting satellite
. Such devices tend to be bulkier than cell-based mobile phones, as they require a large antenna
for communicating with the satellite, but do not require ground based transmitters, making them useful for communicating from remote areas and disaster zones.
There are phones that work as a cordless
phone when near their corresponding base station (and sometimes other base stations) and work as a wireless phone
when in other locations but for a variety of reasons did not become popular.
Some kinds of cordless phones work like cellular phones but only within a small private network covering a building or group of buildings. These kinds of systems using VoIP
are popular in hospitals and factories where the same wireless network can be used for both data and voice.
IP Telephonyright|thumb|125px|A VoIP
Also known as Internet
telephony, IP Telephony is a service based on Voice over IP
(VoIP), a disruptive technology
that is rapidly gaining ground against traditional telephone network technologies. In Japan
and South Korea
up to 10% of subscribers, as of January 2005
, have switched to this digital telephone service. A recent Newsweek
article suggested that Internet telephony may be "the next big thing." http://msnbc.msn.com/id/6831938/site/newsweek/
There are many IP Telephony providers in the market (such as Packet8
, and Sunrocket
) at the moment, and statistics suggest over 40% of the world population will have switched to VoIP by year
IP telephony uses a broadband Internet
connection to transmit conversations as data packet
s. In addition to replacing POTS, IP telephony is also competing with mobile phone
networks by offering free or lower cost connections via WiFi hotspot
s. As mentioned above VoIP
is also used on private wireless networks which may or may not have a connection to the outside telephone network.
Telephone equipment research labsBell Labs
is a noted telephone equipment research laboratory, amongst its other research fields.
Telephone operating companies
In some countries, many telephone operating companies (commonly abbreviated to telco
in American English) are in competition to provide telephone
services. Some of them are included in the following list. However, the list only includes facilities based providers and not companies which lease services from facilities based providers in order to serve their customers. See also
: List of telephone operating companies
*The modern handset came into existence when a Swedish lineman
tied a microphone and earphone to a stick so he could keep a hand free.
*The folding portable phone was an intentional copy of the fictional futuristic communicators (which in use actually more closely resembled walkie-talkie
-style) used in the television show Star Trek
, though similar devices were seen in other TV shows before that.
, telephones are depicted with the characters whose hexadecimal
codes are 2121 (℡), 260E (☎), 260F (☏) and 2706 ), (but may not display properly in some browsers).
* Answering machine
* Cordless telephone
* Cellular repeater
* Emergency telephone
* Pen register
* Telecommunications Device for the Deaf
(TDD or TTY)
* Electronic Switching System
* Field telephone
Telephone equipment manufacturers
Several manufacturers build telephones of all kinds. Some of these are:
*Advanced American Telephones
(makers of AT&T
/ Lucent Technologies
(makers of amplified telephones)
(makers of Southwestern Bell
(makers of Northwestern Bell
(makers of BellSouth
* Asymmetric Digital Subscriber Line
* Automatic Call Distribution
* AIOD leads
* Assistive technology
* Automatic redial
* Call capture
* Call forwarding
* Call waiting
* Caller ID
* Call-through telecom
* Computer telephony integration
* Customer premises equipment
* Dial tone
* Digital subscriber line
* Direct dial
* Direct distance dialing
* Dual tone multi frequency
* Interactive Voice Response
* Last Call Return
* Party line (telephony)
* Plain old telephone service
* Ringing signal
* Signal strength
* Telephone feature code
* Voice over Internet Protocol
Telephone system, organization, and structure
* Area code
* Office code
* Basic exchange telecommunications radio service
* Bell System
* Call center
* Competitive local exchange carrier
* Foreign exchange service
* Incumbent local exchange company
* Key system
* Local exchange company
* Public Switched Telephone Network
* Regional Bell operating company
* Post office
* Private line
* Private branch exchange
* Station set
Telephone hacking and exploitation
* Blue box
* Bomb threat
* Caller ID spoofing
* Crank (or prank) call
* Demon dialing
* (Phone) phreaking
* Speed dialer
* Telephone fraud
* Unsolicited Telemarketing
* War dialing
Telephony in the USA
* Competitive local exchange carrier
* Federal Standard 1037C
* Interexchange carrier
* List of telephony terms
* Local access and transport area
* Local exchange carrier
* Modification of Final Judgment
* Federal Regulations - Part 68
* Regional Bell operating company
Telephony outside the USA
* Telecommunications industry in China
* Call originator
* Call waiting
* Called party
* Calling party
* Circuit busy
* Emergency telephone number
* End instrument
* Help desk
* Hook Flash
* Hunt Group
* Interactive voice response
* Local loop
* Long-distance operator
* Operator assistance
* Red telephone
, Red telephone box
* Ringer equivalency number
* Ringing signal
* Rural radio service
* Telephone booth
* Telephone call
* Telephone card
* Telephone directory
* Telephone exchange
* Telephone tapping
* Telephone User Interface
* Telephony Application Programming Interface
* Trap and trace
* Vertical service code
* Western Union
* Wide Area Telephone Service
* WATS line
* Wireless network
* Zenith number
* registered jack
* BS 6312
There are many standards for common carrier wireless telephony, often with incompatible standards used in the same nation:
* First generation - Analog
** marine and mobile radio telephony
* Satellite systems- digital
** Iridium (satellite)
* Second generation (2G
) - Digital
** CDMA IS-95A
, (different frequencies for different continents: see GSM article)
** TDMA IS-136
** CDMA IS-95B
* Third generation (3G
** CDMA 2000
, also called W-CDMA
* Flat rate
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0174465 US 174,465
(Bell's first telephone patent) -- Alexander Graham Bell
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0186787 US 186,787
-- Electric Telegraphy
(permanent magnet receiver) -- Alexander Graham Bell
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0474230 US 474,230
-- Speaking Telegraph
(graphite transmitter) -- Thomas Edison
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0203016 US 203,016
-- Speaking Telephone
(carbon button transmitter) -- Thomas Edison
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0222390 US 222,390
-- Carbon Telephone
(carbon granules transmitter) -- Thomas Edison
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=0485311 US 485,311
(solid back carbon transmitter) -- Anthony C. White (Bell engineer) This design was used until 1925 and installed phones were used until the 1940's.
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=3449750 US 3,449,750
-- Duplex Radio Communication and Signalling Appartus
-- G. H. Sweigert
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=3663762 US 3,663,762
-- Cellular Mobile Communication System
-- Amos Edward Joel (Bell Labs)
* http://patft1.uspto.gov/netacgi/nph-Parser?patentnumber=3906166 US 3,906,166
-- Radio Telephone System
(DynaTAC cell phone) -- Martin Cooper et al. (Motorola)
* Coe, Lewis (1995), The Telephone and Its Several Inventors: A History
, McFarland, North Carolina, 1995. ISBN 0-7864-0138-9
* Evenson, A. Edward (2000), The Telephone Patent Conspiracy of 1876: The Elisha Gray - Alexander Bell Controversy
, McFarland, North Carolina, 2000. ISBN 0-7864-0883-9
* Baker, Burton H. (2000), The Gray Matter: The Forgotten Story of the Telephone
, Telepress, St. Joseph, MI, 2000. ISBN 0-615-11329-X
* Huurdeman, Anton A. (2003), The Worldwide History of Telecommunications
, IEEE Press and J. Wiley & Sons, 2003. ISBN 0-471-20505-2
* Josephson, Matthew (1992), Edison: A Biography
, Wiley, 1992. ISBN 0-471-54806-5
* Bruce, Robert V. (1990), Alexander Graham Bell and the Conquest of Solitude
, Cornell University Press, Ithaca, 1990.
*Robert Sobel The Entrepreneurs: Explorations Within the American Business Tradition
(Weybright & Talley 1974
), ISBN 0-679-40064-8.
See AlsoHistory of telephone
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