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1947 Telephone strike
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The 1947 Telephone strike was a five-week long, nation-wide labor stoppage in the United States by the National Federation of Telephone Workers (NFTW) and other smaller unions that started on… [see Wikipedia article]
1983 AT&T strike
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The 1983 AT&T strike was a nationwide strike of 675,000 telephone workers across the United States that followed a breakdown in contract negotiations with the American telecommunications company AT&T. [see Wikipedia article]
911 (emergency telephone number)
911, sometimes written 9-1-1, is an emergency telephone number in Canada and the United States, one of eight N11 codes of the North American Numbering Plan (NANP). Dialing 911 from… [see Wikipedia article]
A
Acoustic telegraphy
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Acoustic telegraphy was a name for various methods of multiplexing telegraph messages simultaneously over a single telegraph wire by using different audio frequencies or channels for each message. A telegrapher… [see Wikipedia article]
Adaptive equalizer
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An adaptive equalizer is an equalizer that automatically adapts to time-varying properties of the communication channel. It is frequently used with coherent modulations such as phase-shift keying, mitigating the effects… [see Wikipedia article]
Advanced Mobile Phone System
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Advanced Mobile Phone System (AMPS) was an analog mobile phone system standard originally developed by Bell Labs and later modified in a cooperative effort between Bell Labs and Motorola. It… [see Wikipedia article]
Answering machine
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An answering machine, answerphone, or message machine, also known as telephone messaging machine in the UK and some Commonwealth countries, ansaphone or ansafone, or telephone answering device (TAD), is used… [see Wikipedia article]
Audion
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The Audion is an electronic detecting or amplifying vacuum tube invented by American electrical engineer Lee de Forest as a diode in 1906. Improved, it was patented as the first… [see Wikipedia article]
B
Blue box
A blue box is an electronic device that produces tones used to generate the in-band signaling tones formerly used within the North American long-distance telephone network to send line status… [see Wikipedia article]
Breakup of the Bell System
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The Bell System held a virtual monopoly over telephone infrastructure in the United States from around the early 20th century until January 8, 1982. It consisted of the parent American… [see Wikipedia article]
C
C (programming language)
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C is a general-purpose programming language created in the 1970s by Dennis Ritchie. By design, C gives the programmer relatively direct access to the features of the typical CPU architecture,… [see Wikipedia article]
Caller ID
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Caller identification 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… [see Wikipedia article]
Candlestick telephone
The candlestick telephone is a style of telephone that was common from the late 1890s to the 1940s. A candlestick telephone is also often referred to as a desk stand,… [see Wikipedia article]
Carbon microphone
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The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It… [see Wikipedia article]
Carterfone
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The Carterfone is a device invented by Thomas Carter. It connects a two-way radio system to the telephone system, allowing someone on the radio to talk to someone on the… [see Wikipedia article]
Charge-coupled device
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A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. Under the control of an external circuit, each capacitor can transfer its electric charge… [see Wikipedia article]
Coaxial cable
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Coaxial cable, or coax, is a type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric ; many… [see Wikipedia article]
Common battery
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In telecommunications, a common battery is a single electrical power source used to energize more than one circuit, electronic component, equipment, or system. [see Wikipedia article]
Common-channel signaling
In telecommunications, common-channel signaling (CCS), or common-channel interoffice signaling (CCIS), is the transmission of control information (signaling) via a separate channel than that used for the messages, The signaling channel… [see Wikipedia article]
Communications Act of 1934
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The Communications Act of 1934 is a United States federal law signed by President Franklin D. Roosevelt on June 19, 1934, and codified as Chapter 5 of Title 47 of… [see Wikipedia article]
Communications Workers of America
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The Communications Workers of America (CWA) is the largest communications and media labor union in the United States, representing about 700,000 members in both the private and public sectors. The… [see Wikipedia article]
Cosmic microwave background
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The cosmic microwave background, or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies… [see Wikipedia article]
Courtesy telephone
A courtesy telephone is a telephone located in airport terminals, large train stations, hotel lobbies, and other places where many travellers are expected, which is used to relay messages to… [see Wikipedia article]
Crossbar switch
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In electronics and telecommunications, a crossbar switch is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed… [see Wikipedia article]
D
Direct distance dialing
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Direct distance dialing (DDD) is a telecommunications service in North America by which a caller may call any other subscriber outside the local calling area without operator assistance, DDD was… [see Wikipedia article]
DMS-100
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The DMS-100 is a member of the Digital Multiplex System (DMS) product line of telephone exchange switches manufactured by Northern Telecom. Designed during the 1970s and released in 1979, it… [see Wikipedia article]
Dry cell
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A dry cell is a type of electric battery, commonly used for portable electrical devices. Unlike wet cell batteries, which have a liquid electrolyte, dry cells use an electrolyte in… [see Wikipedia article]
DTMF signaling
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Dual-tone multi-frequency (DTMF) signaling is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed… [see Wikipedia article]
E
Echo suppression and cancellation
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Echo suppression and echo cancellation are methods used in telephony to improve voice quality by preventing echo from being created or removing it after it is already present. In addition… [see Wikipedia article]
Electrical telegraph
Electrical telegraphy is point-to-point distance communicating via sending electric signals over wire, a system primarily used from the 1840s until the late 20th century. It was the first electrical telecommunications… [see Wikipedia article]
Electronic switching system
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In telecommunications, an electronic switching system (ESS) is a telephone switch that uses solid-state electronics, such as digital electronics and computerized common control, to interconnect telephone circuits for the purpose… [see Wikipedia article]
Ethernet
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Ethernet is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in… [see Wikipedia article]
F
First transcontinental telephone call
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A telephone call, which for marketing purposes is claimed to be the first transcontinental telephone call, occurred on January 25, 1915, a day timed to coincide with the Panama–Pacific International… [see Wikipedia article]
Frequency-hopping spread spectrum
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Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly changing the carrier frequency among many frequencies occupying a large spectral band. The changes are controlled by… [see Wikipedia article]
G
GSM
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The Global System for Mobile Communications (GSM) is a family of standards to describe the protocols for second-generation (2G) digital cellular networks, as used by mobile devices such as mobile… [see Wikipedia article]
H
Handover
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In cellular telecommunications, handover, or handoff, is the process of transferring an ongoing call or data session from one channel connected to the core network to another channel. In satellite… [see Wikipedia article]
Hawthorne Works
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The Hawthorne Works was a large factory complex of the Western Electric Company in Cicero, Illinois. In addition to industrial plants, several on-site community amenities were provided to workers. Named… [see Wikipedia article]
I
In-band signaling
In telecommunications, in-band signaling is the sending of control information within the same band or channel used for data such as voice or video. This is in contrast to out-of-band… [see Wikipedia article]
Independent telephone company
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An independent telephone company was a telephone company providing local service in the United States or Canada that was not part of the Bell System organized by American Telephone and… [see Wikipedia article]
Integrated Services Digital Network
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Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public… [see Wikipedia article]
Intelsat
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Intelsat S.A. is a Luxembourgish-American multinational satellite services provider with corporate headquarters in Luxembourg and administrative headquarters in Tysons, Virginia, United States. Originally formed as International Telecommunications Satellite Organization, from… [see Wikipedia article]
Intelsat I
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Intelsat I was the first commercial communications satellite to be placed in geosynchronous orbit, on April 6, 1965. It was built by the Space and Communications Group of Hughes Aircraft… [see Wikipedia article]
Internet protocol suite
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The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational… [see Wikipedia article]
K
Kingsbury Commitment
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The Kingsbury Commitment is a 1913 out-of-court settlement of the United States government's antitrust challenge against the American Telephone and Telegraph Company (AT&T) for the company's then-growing vertical monopoly in… [see Wikipedia article]
L
Landline
A landline, or fixed line, is telephone service provided to a subscriber via cable or wire, i.e. metal conductors or optical fiber. The term differentiates a telephone service from the… [see Wikipedia article]
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word laser originated as an acronym for… [see Wikipedia article]
Loading coil
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A loading coil, or load coil, is an inductor that is inserted into an electronic circuit to increase its inductance. The term originated in the 19th century for inductors used… [see Wikipedia article]
Local loop
In telephony, the local loop is the physical link or circuit that connects from the demarcation point of the customer premises to the edge of the common carrier or telecommunications… [see Wikipedia article]
Local number portability
Local number portability (LNP) for fixed lines, and full mobile number portability (FMNP) for mobile phone lines, refers to the ability of a "customer of record" of an existing fixed-line… [see Wikipedia article]
Long-distance calling
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In telecommunications, a long-distance call (U.S.) or trunk call is a telephone call made to a location outside a defined local calling area. Long-distance calls are typically charged a higher… [see Wikipedia article]
M
m-derived filter
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m-derived filters or m-type filters are a type of electronic filter designed using the image method. They were invented by Otto Zobel in the early 1920s. This filter type was… [see Wikipedia article]
Maser
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A maser is a device that produces coherent electromagnetic waves (microwaves), through amplification by stimulated emission. The term is an acronym for microwave amplification by stimulated emission of radiation. Nikolay… [see Wikipedia article]
Microwave transmission
Microwave transmission is the transmission of information by electromagnetic waves with wavelengths in the microwave frequency range of 300 MHz to 300 GHz of the electromagnetic spectrum. Microwave signals are normally limited… [see Wikipedia article]
Minitel
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Minitel, officially known as TELETEL, was an interactive videotex online service accessible through telephone lines. It was the world's first and most successful mass-market online service prior to the World… [see Wikipedia article]
Mobile Telephone Service
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The Mobile Telephone Service (MTS) was a pre-cellular VHF radio system that linked to the Public Switched Telephone Network (PSTN). MTS was the radiotelephone equivalent of land dial phone service. [see Wikipedia article]
Modular connector
A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such as in computer networking, telecommunication equipment, and audio headsets. [see Wikipedia article]
MOSFET
In electronics, the metal–oxide–semiconductor field-effect transistor is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of… [see Wikipedia article]
Multi-frequency signaling
In telephony, multi-frequency signaling (MF) is a type of signaling that was introduced by the Bell System after World War II. It was in use since before 1949. It uses… [see Wikipedia article]
Multiplexing
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In telecommunications and computer networking, multiplexing is a method by which multiple analog or digital signals are combined into one signal over a transmission medium. It allows the same medium… [see Wikipedia article]
N
Negative-feedback amplifier
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A negative-feedback amplifier is an electronic amplifier that subtracts a fraction of its output from its input, so that negative feedback opposes the original signal. The applied negative feedback can… [see Wikipedia article]
Nordic Mobile Telephone
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NMT is an automatic cellular phone system specified by Nordic telecommunications administrations (PTTs) and opened for service on 1 October 1981. NMT is based on analogue technology and two variants… [see Wikipedia article]
Number 4ESS switch
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The No. 4 Electronic Switching System (4ESS) is a class 4 telephone electronic switching system that was the first digital electronic toll switch introduced by Western Electric for long-distance switching.… [see Wikipedia article]
Number Five Crossbar Switching System
The Number Five Crossbar Switching System is a telephone switch for telephone exchanges designed by Bell Labs and manufactured by Western Electric starting in 1947. It was used in the… [see Wikipedia article]
Number One Electronic Switching System
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The Number One Electronic Switching System (1ESS) was the first large-scale stored program control (SPC) telephone exchange or electronic switching system in the Bell System. It was manufactured by Western… [see Wikipedia article]
O
Optical fiber
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An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers are widely used in fiber-optic… [see Wikipedia article]
P
Panic of 1907
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The Panic of 1907, also known as the 1907 Bankers' Panic or Knickerbocker Crisis, was a financial crisis that took place in the United States over a three-week period starting… [see Wikipedia article]
Party line (telephony)
A party line is a local loop telephone circuit that is shared by multiple telephone service subscribers. [see Wikipedia article]
Payphone
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A payphone is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic public areas. Prepayment is required by inserting coins or telephone tokens, swiping a… [see Wikipedia article]
Photophone
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The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter… [see Wikipedia article]
Phreaking
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Phreaking is a slang term coined to describe the activity of a culture of people who study, experiment with, or explore telecommunication systems, such as equipment and systems connected to… [see Wikipedia article]
Picturephone
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The videophone as a concept began to materialize shortly after the telephone was patented in 1876, and its history is closely connected to that of the telephone. Many attempts were… [see Wikipedia article]
Plain old telephone service
Plain old telephone service (POTS), or rarely publicly offered telephone service, is a retronym for voice-grade telephone service that employs analog signal transmission over copper loops. [see Wikipedia article]
Public switched telephone network
The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for… [see Wikipedia article]
Pulse dialing
Pulse dialing is a signaling technology in telecommunications in which the direct current flowing in the telephone local loop circuit is interrupted in a pattern according to a coding system… [see Wikipedia article]
Pulse-code modulation
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Pulse-code modulation (PCM) is a method used to digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio… [see Wikipedia article]
Push-button telephone
A push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to a rotary dial used in earlier telephones. [see Wikipedia article]
Q
Quadruplex telegraph
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The Quadruplex telegraph is a type of electrical telegraph which allows a total of four separate signals to be transmitted and received on a single wire at the same time.… [see Wikipedia article]
R
Red telephone box
The red telephone box is a telephone kiosk for a public telephone designed by Sir Giles Gilbert Scott, the architect responsible for famous sites like Liverpool Cathedral and Battersea Power… [see Wikipedia article]
Reis telephone
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The Reis telephone was an early sound transmitting device, invented by Philipp Reis in 1857. Reis's first successful work is dated to October 1861. When properly set up, it would… [see Wikipedia article]
Ringer box
A ringer box is a telephone signaling device, similar to a bell box. It usually contains an electromechanical gong and was used with most early desk stand telephones, such as… [see Wikipedia article]
Rotary dial
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A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing. It is used when initiating a… [see Wikipedia article]
S
Sidetone
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Sidetone is audible feedback to someone speaking or otherwise producing sound as an indication of active transmission. Sidetone is introduced by some communications circuits and anti-sidetone circuitry is used to… [see Wikipedia article]
Signalling System No. 7
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Signalling System No. 7 (SS7) is a set of telephony signaling protocols developed in the 1970s that is used to setup and teardown telephone calls on most parts of the… [see Wikipedia article]
SMS
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Short Message Service (SMS) is a text messaging service component of most telephone, Internet and mobile device systems. It uses standardized communication protocols that let mobile phones exchange short text… [see Wikipedia article]
Sound-powered telephone
A sound-powered telephone is a communication device that allows users to talk to each other with the use of a handset, similar to a conventional telephone, but without the use… [see Wikipedia article]
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. [see Wikipedia article]
Strowger switch
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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… [see Wikipedia article]
Submarine communications cable
A submarine communications cable is a cable laid on the seabed between land-based stations to carry telecommunication signals across stretches of ocean and sea. [see Wikipedia article]
Switchboard operator
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In the early days of telephony, companies used manual telephone switchboards, and switchboard operators connected calls by inserting a pair of phone plugs into the appropriate jacks. They were gradually… [see Wikipedia article]
T
T-carrier
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The T-carrier system is a member of the series of data-multiplexing carrier systems developed by AT&T Bell Laboratories for digital transmission of multiplexed telephone calls. [see Wikipedia article]
TAT-1
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TAT-1 was the first submarine transatlantic telephone cable system. It was laid between Kerrera, Oban, Scotland, and Clarenville, Newfoundland. Two cables were laid between 1955 and 1956 with one cable… [see Wikipedia article]
TAT-8
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TAT-8 was the 8th transatlantic communications cable and first transatlantic fiber-optic cable, carrying 280 Mbit/s between the United States, United Kingdom and France. It was constructed in 1988 by a consortium… [see Wikipedia article]
Telecommunications Act of 1996
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The Telecommunications Act of 1996 is a United States federal law enacted by the 104th United States Congress on January 3, 1996, and signed into law on February 8, 1996… [see Wikipedia article]
Telephone
A telephone, commonly shortened to phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard… [see Wikipedia article]
Telephone booth
A telephone booth, phone booth, telephone kiosk, telephone call box, telephone box or public call box is a tiny structure furnished with a payphone and designed for a telephone user's… [see Wikipedia article]
Telephone directory
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A telephone directory, commonly called a telephone book, telephone address book or phonebook, is a listing of telephone subscribers in a geographical area or subscribers to services provided by the… [see Wikipedia article]
Telephone exchange
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A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the… [see Wikipedia article]
Telephone exchange names
A telephone exchange name or central office name was a distinguishing and memorable name assigned to a central office. It identified the switching system to which a telephone was connected,… [see Wikipedia article]
Telephone magneto
A telephone magneto is a hand-cranked electrical generator that uses permanent magnets to produce alternating current from a rotating armature. In early telegraphy, magnetos were used to power instruments, while… [see Wikipedia article]
Telephone number
A telephone number is the address of a telecommunication endpoint, such as a telephone, in a telephone network, such as the public switched telephone network (PSTN). A telephone number typically… [see Wikipedia article]
Telephone numbering plan
A telephone numbering plan is a type of numbering scheme used in a telecommunications network to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the… [see Wikipedia article]
Telephone switchboard
A telephone switchboard is a device used to connect circuits of telephones to establish telephone calls between users or other switchboards. The switchboard is an essential component of a manual… [see Wikipedia article]
Telex
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Telex is a telecommunication system that allows text-based messages to be sent and received by teleprinter over telephone lines. The term "telex" may refer to the service, the network, the… [see Wikipedia article]
Telstar
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Telstar is a series of communications satellites. The first two, Telstar 1 and Telstar 2, were experimental and nearly identical. Telstar 1 was launched atop a Thor-Delta rocket on July… [see Wikipedia article]
Tin-can telephone
A tin-can telephone is a type of acoustic (non-electrical) speech-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut… [see Wikipedia article]
Traffic Service Position System
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The Traffic Service Position System (TSPS) was developed by Bell Labs in Columbus, Ohio to replace traditional cord switchboards. The first TSPS was deployed in Morristown, New Jersey in 1969… [see Wikipedia article]
Transistor
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A transistor is a semiconductor device with at least three terminals for connection to an electric circuit. In the common case, the third terminal controls the flow of current between… [see Wikipedia article]
Twisted pair
Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a… [see Wikipedia article]
U
United States v. AT&T (1982)
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United States v. AT&T, 552 F.Supp. 131 (1982), was a ruling of the United States District Court for the District of Columbia, that led to the 1984 Bell System divestiture,… [see Wikipedia article]
Unix
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Unix is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, the development of which started in 1969 at the Bell Labs research center… [see Wikipedia article]
V
Vacuum tube
A vacuum tube, electron tube, thermionic valve, or tube is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has… [see Wikipedia article]
Videotex
Videotex was one of the earliest implementations of an end-user information system. From the late 1970s to early 2010s, it was used to deliver information to a user in computer-like… [see Wikipedia article]
Vocoder
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A vocoder is a category of speech coding that analyzes and synthesizes the human voice signal for audio data compression, multiplexing, voice encryption or voice transformation. [see Wikipedia article]
Voder
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The Bell Telephone Laboratory's voder was the first attempt to electronically synthesize human speech by breaking it down into its acoustic components. It was invented by Homer Dudley in 1937–1938… [see Wikipedia article]
Voice over IP
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Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet.… [see Wikipedia article]
W
Water microphone
A water microphone or water transmitter is based on Ohm's law that current in a wire varies inversely with the resistance of the circuit. The sound waves from a human… [see Wikipedia article]