A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced intelligible replication of the human voice; this instrument was further developed by many others. The telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones became indispensable to businesses and households and are today some of the most used small appliances; the essential elements of a telephone are a microphone to speak into and an earphone which reproduces the voice in a distant location. In addition, most telephones contain a ringer to announce an incoming telephone call, a dial or keypad to enter a telephone number when initiating a call to another telephone.
The receiver and transmitter are built into a handset, held up to the ear and mouth during conversation. The dial may be located either on a base unit to which the handset is connected; the transmitter converts the sound waves to electrical signals which are sent through a telephone network to the receiving telephone, which converts the signals into audible sound in the receiver or sometimes a loudspeaker. Telephones are duplex devices; 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 replaced by manually operated centrally located switchboards; these exchanges were soon connected together 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 phones were introduced for personal service starting in 1973.
In decades their analog cellular system evolved into digital networks with greater capability and lower cost. Convergence has given most modern cell phones capabilities far beyond simple voice conversation, they may be able to record spoken messages and receive text messages and display photographs or video, play music or games, surf the Internet, do road navigation or immerse the user in virtual reality. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication and computing needs. A traditional landline telephone system known as plain old telephone service carries both control and audio signals on the same twisted pair of insulated wires, the telephone line; the control and signaling equipment consists of three components, the ringer, the hookswitch, a dial. The ringer, or beeper, light or other device, alerts the user to incoming calls; the hookswitch signals to the central office that the user has picked up the handset to either answer a call or initiate a call.
A dial, if present, is used by the subscriber to transmit a telephone number to the central office when initiating a call. Until the 1960s dials used exclusively the rotary technology, replaced by dual-tone multi-frequency signaling with pushbutton telephones. A major expense of wire-line telephone service is the outside wire plant. Telephones transmit both the outgoing speech signals on a single pair of wires. A twisted pair line rejects electromagnetic interference and crosstalk better than a single wire or an untwisted pair; the strong outgoing speech signal from the microphone does not overpower the weaker incoming speaker signal with sidetone because a hybrid coil and other components compensate the imbalance. The junction box arrests lightning and adjusts the line's resistance to maximize the signal power for the line length. Telephones have similar adjustments for inside line lengths; the line voltages are negative compared to earth. Negative voltage attracts positive metal ions toward the wires.
The landline telephone contains a switchhook and an alerting device a ringer, that remains connected to the phone line whenever the phone is "on hook", other components which are connected when the phone is "off hook". The off-hook components include a transmitter, a receiver, other circuits for dialing and amplification. A calling party wishing to speak to another party will pick up the telephone's handset, thereby operating a lever which closes the switchhook, which powers the telephone by connecting the transmitter and related audio components to the line; the off-hook circuitry has a low resistance which causes a direct current, which comes down the line from the telephone exchange. The exchange detects this current, attaches a digit receiver circuit to the line, sends a dial tone to indicate readiness. On a modern push-button telephone, the caller presses the number keys to send the telephone number of the called party; the keys control a tone generator circuit. A rotary-dial telephone uses pulse
NTT Docomo Inc. is the predominant mobile phone operator in Japan. The name is an abbreviation of the phrase, "do communications over the mobile network", is from a compound word dokomo, meaning "everywhere" in Japanese. Docomo provides phone, video phone, i-mode, mail services; the company's headquarters are in the Sanno Park Tower, Nagatachō, Tokyo. Docomo was spun off from Nippon Telegraph and Telephone in August 1991 to take over the mobile cellular operations, it provides 3G W-CDMA services and 4G LTE services. Its businesses included PHS, satellite. Docomo ceased offering a PHS service on January 7, 2008. NTT Docomo is a subsidiary of Japan's incumbent telephone operator, NTT; the majority of NTT Docomo's shares are owned by NTT. While some NTT shares are publicly traded, control of the company by Japanese interests is guaranteed by the number of shares available to buyers, it provides wireless voice and data communications to subscribers in Japan. NTT Docomo is the creator of W-CDMA technology as well as mobile i-mode service.
In late 1995, Docomo CEO hired the consulting firm PricewaterhouseCoopers for strategy development, at that time worked on the first design of data services on mobile for NTT Docomo CEO. NTT Docomo has more than 53 million customers, more than half of Japan's cellular market; the company provides a wide variety of mobile multimedia services. These include i-mode which provides e-mail and internet access to over 50 million subscribers, FOMA, launched in 2001 as the world's first 3G mobile service based on W-CDMA, Xi, a 4G LTE mobile service, launched on December 24, 2010, Premium 4G, a LTE Advanced service, launched on March 27, 2015. In addition to wholly owned subsidiaries in Europe and North America, the company is expanding its global reach through strategic alliances with mobile and multimedia service providers in Asia-Pacific and Europe. NTT Docomo is listed on the Tokyo and New York stock exchanges. On April 19, 2008, it was announced that Ryuji Yamada, the current co-president of NTT Docomo, will be promoted as the president of NTT Docomo in June 2008.
Masao Nakamura will stay in NTT Docomo as a director and the senior adviser. Since October 2006, when the introduction to the service which allows the user to carry their original phone number with a new provider was made, NTT Docomo has lost many users to KDDI and SoftBank; this promotion was made in order to get more users for NTT Docomo. The company was the last major global mobile carrier to offer Apple's iPhone, which it did with the release of the iPhone 5s and 5c; this has been cited as one of the reasons for the steady stream of its customers switching for competing networks. In June 2011, the company announced that they were teaming up with McAfee to provide McAfee VirusScan Mobile for its Android mobile users. In July 2012, NTT Docomo acquired Italy's Buongiorno in a deal worth 209 million euros. On October 2007, the prototype Wellness mobile phone of Japan's NTT Docomo Inc. and Mitsubishi Electric Corp. was launched at CEATEC. It checks health with a motion sensor that detects body movement and measures calories, includes a breathalyzer.
On January 24, 2008, NTT Docomo announced a partnership with Google, which allowed all models after the FOMA904i models to view YouTube videos. NTT Docomo is a founding member of the Symbian Foundation. From 2008, Docomo began offering a service called the "Area Mail Disaster Information Service" which broadcasts Earthquake Early Warning messages produced by the Japan Meteorological Agency to its subscribers with compatible handsets; this service is provided free of charge and messages are limited to those areas affected by each particular alert. These alerts have a unique ring tone so they can be distinguished from incoming calls or messages. From 2014, under Civil Protection Law of Japan, Docomo began offering a service called the "Area Mail Disaster and Evacuation Information Service" which broadcasts J-Alert messages produced by the Japan Fire and Disaster Management Agency to its subscribers with compatible handsets; the message is broadcast when the military threat is imminent, volcanic eruptions, or approaching tsunami.
The company's mascot is Docomodake, a mushroom, quite a celebrity in Japan. He is the hero of a Nintendo DS puzzle and platforming video game, Boing! Docomodake DS on 2007 and 2009, he has a wide variety of merchandising such as cell phone straps and plush dolls. As one type of advertising method, there are many types of Docomodakes such as mother and father, which symbolizes the plans that NTT Docomo offers. Emoji, a pictographic language being adopted around the world was first created by NTT DoCoMo; the first emoji was created in 1998 or 1999 by Shigetaka Kurita, part of the team working on NTT DoCoMo's i-mode mobile Internet platform. The first set of 176 12×12 pixel emoji was created as part of i-mode's messaging features to help facilitate electronic communication, to serve as a distinguishing feature from other services. NTT Docomo has a wide range of foreign investments. However, NTT Docomo was not successful in investing in foreign carriers. Docomo had invested large multibillion-dolla
The music industry consists of the companies and individuals that earn money by creating new songs and pieces and selling live concerts and shows and video recordings and sheet music, the organizations and associations that aid and represent music creators. Among the many individuals and organizations that operate in the industry are: the songwriters and composers who create new songs and musical pieces; the industry includes a range of professionals who assist singers and musicians with their music careers. In addition to the businesses and artists who work in the music industry to make a profit or income, there is a range of organizations that play an important role in the music industry, including musician's unions, not-for-profit performance-rights organizations and other associations; the modern Western music industry emerged between the 1930s and 1950s, when records replaced sheet music as the most important product in the music business. In the commercial world, "the recording industry"—a reference to recording performances of songs and pieces and selling the recordings–began to be used as a loose synonym for "the music industry".
In the 2000s, a majority of the music market is controlled by three major corporate labels: the French-owned Universal Music Group, the Japanese-owned Sony Music Entertainment, the US-owned Warner Music Group. Labels outside of these three major labels are referred to as independent labels; the largest portion of the live music market for concerts and tours is controlled by Live Nation, the largest promoter and music venue owner. Live Nation is a former subsidiary of iHeartMedia Inc, the largest owner of radio stations in the United States. In the first decades of the 2000s, the music industry underwent drastic changes with the advent of widespread digital distribution of music via the Internet. A conspicuous indicator of these changes is total music sales: since 2000, sales of recorded music have dropped off while live music has increased in importance. In 2011, the largest recorded music retailer in the world was now a digital, Internet-based platform operated by a computer company: Apple Inc.'s online iTunes Store.
Since 2011, the Music Industry has seen consistent sales growth with streaming now generating more revenue per annum than digital downloads. Spotify and Apple lead the way with online digital streaming. Printed music in Europe: Music publishing using machine-printed sheet music developed during the Renaissance music era in the mid-15th century; the development of music publication followed the evolution of printing technologies that were first developed for printing regular books. After the mid-15th century, mechanical techniques for printing sheet music were first developed; the earliest example, a set of liturgical chants, dates from about 1465, shortly after the Gutenberg Bible was printed. Prior to this time, music had to be copied out by hand. To copy music notation by hand was a costly, labor-intensive and time-consuming process, so it was undertaken only by monks and priests seeking to preserve sacred music for the church; the few collections of secular music that are extant were commissioned and owned by wealthy aristocrats.
Examples include the Squarcialupi Codex of Italian Trecento music and the Chantilly Codex of French Ars subtilior music. The use of printing enabled sheet music to reproduced much more and at a much lower cost than hand-copying music notation; this helped musical styles to spread to other cities and countries more and it enabled music to be spread to more distant areas. Prior to the invention of music printing, a composer's music might only be known in the city she lived in and its surrounding towns, because only wealthy aristocrats would be able to afford to have hand copies made of her music. With music printing, though, a composer's music could be printed and sold at a low cost to purchasers from a wide geographic area; as sheet music of major composer's pieces and songs began to be printed and distributed in a wider area, this enabled composers and listeners to hear new styles and forms of music. A German composer could buy songs written by an Italian or English composer, an Italian composer could buy pieces written by Dutch composers and learn how they wrote music.
This led to more blending of musical styles from different regions. The pioneer of modern music printing was Ottaviano Petrucci, a printer and publisher, able to secure a twenty-year monopoly on printed music in Venice during the 16th century. Venice was one of music centers during this period, his Harmoni
Nokia Corporation is a Finnish multinational telecommunications, information technology, consumer electronics company, founded in 1865. Nokia's headquarters are in the greater Helsinki metropolitan area. In 2017, Nokia employed 102,000 people across over 100 countries, did business in more than 130 countries, reported annual revenues of around €23 billion. Nokia is a public limited company listed on New York Stock Exchange, it is the world's 415th-largest company measured by 2016 revenues according to the Fortune Global 500, having peaked at 85th place in 2009. It is a component of the Euro Stoxx 50 stock market index; the company has had various industries in over 150 years. It was founded as a pulp mill and had long been associated with rubber and cables, but since the 1990s focuses on large-scale telecommunications infrastructures, technology development, licensing. Nokia is a notable major contributor to the mobile telephony industry, having assisted in the development of the GSM, 3G and LTE standards, is best known for having been the largest worldwide vendor of mobile phones and smartphones for a period.
After a partnership with Microsoft and market struggles, its mobile phone business was bought by the former, creating Microsoft Mobile as its successor in 2014. After the sale, Nokia began to focus more extensively on its telecommunications infrastructure business and on the Internet of things, marked by the divestiture of its Here mapping division and the acquisition of Alcatel-Lucent, including its Bell Labs research organization; the company also experimented with virtual reality and digital health, the latter through the purchase of Withings. The Nokia brand has since returned to the mobile and smartphone market through a licensing arrangement with HMD Global. Nokia continues to be a major patent licensor for most large mobile phone vendors; as of 2018 Nokia is the world's third largest network equipment manufacturer. The company was viewed with national pride by Finns, as its successful mobile phone business made it by far the largest worldwide company and brand from Finland. At its peak in 2000, during the telecoms bubble, Nokia alone accounted for 4% of the country's GDP, 21% of total exports, 70% of the Helsinki Stock Exchange market capital.
Nokia's history dates back to 1865, when Finnish-Swede mining engineer Fredrik Idestam established a pulp mill near the town of Tampere, Finland. A second pulp mill was opened in 1868 near the neighboring town of Nokia, offering better hydropower resources. In 1871, together with friend Leo Mechelin, formed a shared company from it and called it Nokia Ab, after the site of the second pulp mill. Idestam retired in 1896. Mechelin expanded into electricity generation by 1902. In 1904 Suomen Gummitehdas, a rubber business founded by Eduard Polón, established a factory near the town of Nokia and used its name. In 1922, Nokia Ab entered into a partnership with Finnish Rubber Works and Kaapelitehdas, all now jointly under the leadership of Polón. Finnish Rubber Works company grew when it moved to the Nokia region in the 1930s to take advantage of the electrical power supply, the cable company soon did too. Nokia at the time made respirators for both civilian and military use, from the 1930s well into the early 1990s.
In 1967, the three companies - Nokia and Finnish Rubber Works - merged and created a new Nokia Corporation, a new restructured form divided into four major businesses: forestry, cable and electronics. In the early 1970s, it entered the radio industry. Nokia started making military equipment for Finland's defence forces, such as the Sanomalaite M/90 communicator in 1983, the M61 gas mask first developed in the 1960s. Nokia was now making professional mobile radios, telephone switches and chemicals. After Finland's trade agreement with the Soviet Union in the 1960s, Nokia expanded into the Soviet market, it soon widened trade. Nokia co-operated on scientific technology with the Soviet Union; the U. S. government became suspicious of that technologic co-operation after the end of the Cold War détente in the early 1980s. Nokia imported many US-made components and used them for the Soviets, according to U. S. Deputy Minister of Defence, Richard Perle, Nokia had a secret co-operation with The Pentagon that allowed the U.
S. to keep track in technologic developments in the Soviet Union through trading with Nokia. However this was a demonstration of Finland trading with both sides, as it was neutral during the Cold War. In 1977, Kari Kairamo became. By this time Finland were becoming what has been called "Nordic Japan". Under his leadership Nokia acquired many companies. In 1984, Nokia acquired television maker Salora, followed by Swedish electronics and computer maker Luxor AB in 1985, French television maker Oceanic in 1987; this made Nokia the third-largest television manufacturer of Europe. The existing brands continued to be used until the end of the television business in 1996. In 1987, Nokia acquired Schaub-Lorenz, the consumer operations of Germany's Standard Elektrik Lorenz, which included its "Schaub-Lorenz" and "Graetz" brands, it was part of American conglomerate Internationa
Sound recording and reproduction
Sound recording and reproduction is an electrical, electronic, or digital inscription and re-creation of sound waves, such as spoken voice, instrumental music, or sound effects. The two main classes of sound recording technology are analog digital recording. Acoustic analog recording is achieved by a microphone diaphragm that senses changes in atmospheric pressure caused by acoustic sound waves and records them as a mechanical representation of the sound waves on a medium such as a phonograph record. In magnetic tape recording, the sound waves vibrate the microphone diaphragm and are converted into a varying electric current, converted to a varying magnetic field by an electromagnet, which makes a representation of the sound as magnetized areas on a plastic tape with a magnetic coating on it. Analog sound reproduction is the reverse process, with a bigger loudspeaker diaphragm causing changes to atmospheric pressure to form acoustic sound waves. Digital recording and reproduction converts the analog sound signal picked up by the microphone to a digital form by the process of sampling.
This lets the audio data be transmitted by a wider variety of media. Digital recording stores audio as a series of binary numbers representing samples of the amplitude of the audio signal at equal time intervals, at a sample rate high enough to convey all sounds capable of being heard. A digital audio signal must be reconverted to analog form during playback before it is amplified and connected to a loudspeaker to produce sound. Prior to the development of sound recording, there were mechanical systems, such as wind-up music boxes and player pianos, for encoding and reproducing instrumental music. Long before sound was first recorded, music was recorded—first by written music notation also by mechanical devices. Automatic music reproduction traces back as far as the 9th century, when the Banū Mūsā brothers invented the earliest known mechanical musical instrument, in this case, a hydropowered organ that played interchangeable cylinders. According to Charles B. Fowler, this "...cylinder with raised pins on the surface remained the basic device to produce and reproduce music mechanically until the second half of the nineteenth century."
The Banū Mūsā brothers invented an automatic flute player, which appears to have been the first programmable machine. Carvings in the Rosslyn Chapel from the 1560s may represent an early attempt to record the Chladni patterns produced by sound in stone representations, although this theory has not been conclusively proved. In the 14th century, a mechanical bell-ringer controlled by a rotating cylinder was introduced in Flanders. Similar designs appeared in barrel organs, musical clocks, barrel pianos, music boxes. A music box is an automatic musical instrument that produces sounds by the use of a set of pins placed on a revolving cylinder or disc so as to pluck the tuned teeth of a steel comb; the fairground organ, developed in 1892, used a system of accordion-folded punched cardboard books. The player piano, first demonstrated in 1876, used a punched paper scroll that could store a long piece of music; the most sophisticated of the piano rolls were hand-played, meaning that the roll represented the actual performance of an individual, not just a transcription of the sheet music.
This technology to record a live performance onto a piano roll was not developed until 1904. Piano rolls were in continuous mass production from 1896 to 2008. A 1908 U. S. Supreme Court copyright case noted that, in 1902 alone, there were between 70,000 and 75,000 player pianos manufactured, between 1,000,000 and 1,500,000 piano rolls produced; the first device that could record actual sounds as they passed through the air was the phonautograph, patented in 1857 by Parisian inventor Édouard-Léon Scott de Martinville. The earliest known recordings of the human voice are phonautograph recordings, called phonautograms, made in 1857, they consist of sheets of paper with sound-wave-modulated white lines created by a vibrating stylus that cut through a coating of soot as the paper was passed under it. An 1860 phonautogram of Au Clair de la Lune, a French folk song, was played back as sound for the first time in 2008 by scanning it and using software to convert the undulating line, which graphically encoded the sound, into a corresponding digital audio file.
On April 30, 1877, French poet, humorous writer and inventor Charles Cros submitted a sealed envelope containing a letter to the Academy of Sciences in Paris explaining his proposed method, called the paleophone. Though no trace of a working paleophone was found, Cros is remembered as the earliest inventor of a sound recording and reproduction machine; the first practical sound recording and reproduction device was the mechanical phonograph cylinder, invented by Thomas Edison in 1877 and patented in 1878. The invention soon spread across the globe and over the next two decades the commercial recording and sale of sound recordings became a growing new international industry, with the most popular titles selling millions of units by the early 1900s; the development of mass-production techniques enabled cylinder recordings to become a major new consumer item in industrial countries and the cylinder was the main consumer format from the late 1880s until around 1910. The next major technical development was the invention of the gramophone record credited to Emile Berliner and patented in 1887, though others had demonstrated simi
The ohm is the SI derived unit of electrical resistance, named after German physicist Georg Simon Ohm. Although several empirically derived standard units for expressing electrical resistance were developed in connection with early telegraphy practice, the British Association for the Advancement of Science proposed a unit derived from existing units of mass and time and of a convenient size for practical work as early as 1861; the definition of the ohm was revised several times. Today, the definition of the ohm is expressed from the quantum Hall effect; the ohm is defined as an electrical resistance between two points of a conductor when a constant potential difference of one volt, applied to these points, produces in the conductor a current of one ampere, the conductor not being the seat of any electromotive force. Ω = V A = 1 S = W A 2 = V 2 W = s F = H s = J ⋅ s C 2 = kg ⋅ m 2 s ⋅ C 2 = J s ⋅ A 2 = kg ⋅ m 2 s 3 ⋅ A 2 in which the following units appear: volt, siemens, second, henry, kilogram and coulomb.
In many cases the resistance of a conductor in ohms is constant within a certain range of voltages and other parameters. These are called linear resistors. In other cases resistance varies. A vowel of the prefixed units kiloohm and megaohm is omitted, producing kilohm and megohm. In alternating current circuits, electrical impedance is measured in ohms; the siemens is the SI derived unit of electric conductance and admittance known as the mho. The power dissipated by a resistor may be calculated from its resistance, the voltage or current involved; the formula is a combination of Ohm's law and Joule's law: P = V ⋅ I = V 2 R = I 2 ⋅ R where: P is the power R is the resistance V is the voltage across the resistor I is the current through the resistorA linear resistor has a constant resistance value over all applied voltages or currents. Non-linear resistors have a value. Where alternating current is applied to the circuit, the relation above is true at any instant but calculation of average power over an interval of time requires integration of "instantaneous" power over that interval.
Since the ohm belongs to a coherent system of units, when each of these quantities has its corresponding SI unit (watt for P, ohm for R, volt for V and ampere for I, which are related as in § Definition, this formula remains valid numerically when these units are used. The rapid rise of electrotechnology in the last half of the 19th century created a demand for a rational, coherent and international system of units for electrical quantities. Telegraphers and other early users of electricity in the 19th century needed a practical standard unit of measurement for resistance. Resistance was expressed as a multiple of the resistance of a standard length of telegraph wires. Electrical units so defined were not a coherent system with the units for energy, mass and time, requiring conversion factors to be used in calculations relating energy or power to resistance. Two different methods of establishing a system of electrical units can be chosen. Various artifacts, such as a length of wire or a standard electrochemical cell, could be specified as producing defined quantities for resistance, so on.
Alternatively, the electrical units can be related to the mechanical units by defining, for example, a unit of current that gives a specified force between two wires, or a unit of charge that gives a unit of force between two unit charges. This latter method ensures coherence with the units of energy. Defining a unit for resistance, coherent with units of energy and time in effect requires defining units for potential and current, it is desirable that one unit of electrical potential will force one unit of electric current through one unit of electrical resistance, doing one unit of work in one unit of time, otherwi
The Carterfone is a device invented by Thomas Carter. It manually connects a two-way radio system to the telephone system, allowing someone on the radio to talk to someone on the phone; this makes it a direct predecessor to today's autopatch. The device was acoustically, but not electrically, connected to the public switched telephone network, it was electrically connected to the base station of the mobile radio system, got its power from the base station. All electrical parts were encased in an early plastic; when someone on a two-way radio wished to speak to someone on phone, or "landline", the station operator at the base would dial the telephone number. When callers on the radio and on the telephone were both in contact with the base station operator, the handset of the operator's telephone was placed on a cradle built into the Carterfone device. A voice-operated switch in the Carterfone automatically switched on the radio transmitter when the telephone caller was speaking. A separate speaker was attached to the Carterfone to allow the base station operator to monitor the conversation, adjust the voice volume, hang up his telephone when the conversation had ended.
This particular device was involved in a landmark United States regulatory decision related to telecommunications. Twelve years earlier, a court had ruled in the Hush-A-Phone case that devices could mechanically connect to the telephone system without the permission of AT&T. In 1968, the Federal Communications Commission extended this privilege by allowing the Carterfone and other devices to be connected electrically to the AT&T network, as long as they did not cause harm to the system; this ruling called "the Carterfone decision", created the possibility of selling devices that could connect to the phone system using a protective coupler and opened the market to customer-premises equipment. The decision is referred to as "any lawful device", allowing innovations like answering machines, fax machines, modems to proliferate. In February 2007, a petition for rulemaking was filed with the FCC by Skype, requesting the FCC to apply the Carterfone regulations to the wireless industry—which would mean that OEMs, portals and others will be able to offer wireless devices and services without the cellular operators needing to approve the handsets.
However, on 1 April 2008, FCC chairman Kevin Martin indicated. On April 17, 2015 this petition for rulemaking was dismissed without prejudice by the FCC at the request of Skype's current owner, Microsoft Corporation. Autopatch Acoustic coupler Hush-a-Phone v. United States Interconnection Modem Cordless telephone Terminal equipment Telephone Radio Citizens band radio Full text of FCC Carterfone decision Full text of Skype petition Cybertelecom:: Customer Premises Equipment - FCC Regulations concerning attachment and marketing of CPE Timeline from NPR ArsTechnica: Any lawful device - 40 years after the Carterfone decision Carterfone: My Story, by Nicholas Johnson, FCC Commissioner, 1966-73