156-656: Sprint Corporation was an American telecommunications company . Before being acquired by T-Mobile US on April 1, 2020, it was the fourth-largest mobile network operator in the United States, serving 54.3 million customers as of June 30, 2019. The company also offered wireless voice, messaging, and broadband services through its various subsidiaries under the Boost Mobile and Open Mobile brands and wholesale access to its wireless networks to mobile virtual network operators . In July 2013, majority ownership of
312-412: A thermionic tube or thermionic valve uses thermionic emission of electrons from a heated cathode for a number of fundamental electronic functions such as signal amplification and current rectification . The simplest vacuum tube, the diode invented in 1904 by John Ambrose Fleming , contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through
468-414: A core surrounded by a cladding layer, both of which are made of dielectric materials. To confine the optical signal in the core, the refractive index of the core must be greater than that of the cladding. The boundary between the core and cladding may either be abrupt, in step-index fiber , or gradual, in graded-index fiber . Light can be fed into optical fibers using lasers or LEDs . Fiber
624-411: A radio broadcasting station , the station's large power amplifier is the transmitter and the broadcasting antenna is the interface between the power amplifier and the free space channel. The free space channel is the transmission medium and the receiver's antenna is the interface between the free space channel and the receiver. Next, the radio receiver is the destination of the radio signal, where it
780-411: A wavelength shifter collect scintillation light in physics experiments . Fiber-optic sights for handguns, rifles, and shotguns use pieces of optical fiber to improve the visibility of markings on the sight. An optical fiber is a cylindrical dielectric waveguide ( nonconducting waveguide) that transmits light along its axis through the process of total internal reflection. The fiber consists of
936-426: A 16,000-kilometer distance, means that there is a minimum delay of 80 milliseconds (about 1 12 {\displaystyle {\tfrac {1}{12}}} of a second) between when one caller speaks and the other hears. When light traveling in an optically dense medium hits a boundary at a steep angle of incidence (larger than the critical angle for the boundary), the light is completely reflected. This
1092-457: A 33 percent stake in the music streaming service Tidal . Sprint derives revenue as a wireline IP network operator and as a long-distance telephony provider. Sprint is the United States' fourth largest long-distance provider by subscribers. In 2006, Sprint Nextel exited the local landline telephone business, spinning those assets off into a newly created company named Embarq , which CenturyTel acquired in 2008 to form CenturyLink . SprintLink
1248-411: A better price for their goods. In Côte d'Ivoire , coffee growers share mobile phones to follow hourly variations in coffee prices and sell at the best price. On the macroeconomic scale, Lars-Hendrik Röller and Leonard Waverman suggested a causal link between good telecommunication infrastructure and economic growth. Few dispute the existence of a correlation although some argue it is wrong to view
1404-438: A caveat for it in 1876. Gray abandoned his caveat and because he did not contest Bell's priority, the examiner approved Bell's patent on March 3, 1876. Gray had filed his caveat for the variable resistance telephone, but Bell was the first to document the idea and test it in a telephone.[88] Antonio Meucci invented a device that allowed the electrical transmission of voice over a line nearly 30 years before in 1849, but his device
1560-423: A cladding made of pure silica, with an index of 1.444 at 1500 nm, and a core of doped silica with an index around 1.4475. The larger the index of refraction, the slower light travels in that medium. From this information, a simple rule of thumb is that a signal using optical fiber for communication will travel at around 200,000 kilometers per second. Thus a phone call carried by fiber between Sydney and New York,
1716-441: A connection between two or more users. For both types of networks, repeaters may be necessary to amplify or recreate the signal when it is being transmitted over long distances. This is to combat attenuation that can render the signal indistinguishable from the noise. Another advantage of digital systems over analogue is that their output is easier to store in memory, i.e., two voltage states (high and low) are easier to store than
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#17327809019161872-495: A continuous range of states. Telecommunication has a significant social, cultural and economic impact on modern society. In 2008, estimates placed the telecommunication industry 's revenue at US$ 4.7 trillion or just under three per cent of the gross world product (official exchange rate). Several following sections discuss the impact of telecommunication on society. On the microeconomic scale, companies have used telecommunications to help build global business empires. This
2028-451: A digital audio optical connection. This allows the streaming of audio over light, using the S/PDIF protocol over an optical TOSLINK connection. Fibers have many uses in remote sensing . In some applications, the fiber itself is the sensor (the fibers channel optical light to a processing device that analyzes changes in the light's characteristics). In other cases, fiber is used to connect
2184-406: A higher-frequency signal (known as the " carrier wave ") before transmission. There are several different modulation schemes available to achieve this [two of the most basic being amplitude modulation (AM) and frequency modulation (FM)]. An example of this process is a disc jockey's voice being impressed into a 96 MHz carrier wave using frequency modulation (the voice would then be received on
2340-450: A key advantage of digital signals over analogue signals. However, digital systems fail catastrophically when noise exceeds the system's ability to autocorrect. On the other hand, analogue systems fail gracefully: as noise increases, the signal becomes progressively more degraded but still usable. Also, digital transmission of continuous data unavoidably adds quantization noise to the output. This can be reduced, but not eliminated, only at
2496-522: A lasting impact on structures . It is based on the principle of measuring analog attenuation. In spectroscopy , optical fiber bundles transmit light from a spectrometer to a substance that cannot be placed inside the spectrometer itself, in order to analyze its composition. A spectrometer analyzes substances by bouncing light off and through them. By using fibers, a spectrometer can be used to study objects remotely. An optical fiber doped with certain rare-earth elements such as erbium can be used as
2652-429: A loss of 1.3 billion to 3.4 billion dollars. On December 15, 2004, Sprint Corporation and Nextel Communications announced they would merge to form Sprint Nextel Corporation . The merger was transacted as a purchase of Nextel Communications by Sprint Corporation for tax reasons; Sprint purchased 50.1 percent of Nextel. At the time of the merger announcement, Sprint and Nextel were the third and fifth leading providers in
2808-422: A nationwide network to provide wireless personal communications service (PCS), and also affirm their support for a single integrated offering of wireless, local telephone and long distance services in a package with cable television service In 1995, Sprint and its cable television associates entered into a partnership with American Personal Communications (APC) to create a digital wireless network. In November 1995,
2964-423: A network in an office building (see fiber to the office ), fiber-optic cabling can save space in cable ducts. This is because a single fiber can carry much more data than electrical cables such as standard category 5 cable , which typically runs at 100 Mbit/s or 1 Gbit/s speeds. Fibers are often also used for short-distance connections between devices. For example, most high-definition televisions offer
3120-838: A new international frequency list and used in conformity with the Radio Regulation". According to the ITU's Radio Regulations adopted in Atlantic City, all frequencies referenced in the International Frequency Registration Board , examined by the board and registered on the International Frequency List "shall have the right to international protection from harmful interference". From a global perspective, there have been political debates and legislation regarding
3276-790: A new logo. In 2013, following the shutdown of the Nextel network and concurrent with the acquisition by SoftBank, the company resumed using the name Sprint Corporation. In July 2013, as part of the SoftBank transactions, Sprint acquired the remaining shares of the wireless broadband carrier Clearwire Corporation that it did not already own. In August 2014, CEO Dan Hesse was replaced by Marcelo Claure . In May 2018, Michel Combes replaced Claure, and had been working to get Sprint's acquisition by its rival T-Mobile through regulatory proceedings. On April 1, 2020, Sprint Corporation completed their acquisition by T-Mobile US , which effectively made Sprint
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#17327809019163432-437: A person's age, interests, sexual preference and relationship status. In this way, these sites can play important role in everything from organising social engagements to courtship . Prior to social networking sites, technologies like short message service (SMS) and the telephone also had a significant impact on social interactions. In 2000, market research group Ipsos MORI reported that 81% of 15- to 24-year-old SMS users in
3588-491: A radio as the channel "96 FM"). In addition, modulation has the advantage that it may use frequency division multiplexing (FDM). A telecommunications network is a collection of transmitters, receivers, and communications channels that send messages to one another. Some digital communications networks contain one or more routers that work together to transmit information to the correct user. An analogue communications network consists of one or more switches that establish
3744-474: A sensor to a measurement system. Optical fibers can be used as sensors to measure strain , temperature , pressure , and other quantities by modifying a fiber so that the property being measured modulates the intensity , phase , polarization , wavelength , or transit time of light in the fiber. Sensors that vary the intensity of light are the simplest since only a simple source and detector are required. A particularly useful feature of such fiber optic sensors
3900-416: A separate entity, and will remain a CDMA carrier until it is an all-LTE carrier. On April 15, 2013, Dish Network announced a higher bid for Sprint Nextel than the offer placed by SoftBank, with a $ 25.5 billion offer. On June 18, 2013, Dish retracted its bid and decided that it would instead focus on its intent to purchase Clearwire , however on June 26, 2013, Dish also retracted its bid for Clearwire, leaving
4056-475: A service that operated for a year until the gap in the telegraph link was closed. In the Middle Ages, chains of beacons were commonly used on hilltops as a means of relaying a signal. Beacon chains suffered the drawback that they could only pass a single bit of information, so the meaning of the message such as "the enemy has been sighted" had to be agreed upon in advance. One notable instance of their use
4212-423: A strategic alliance with Call-Net Enterprises, a Canadian long-distance service provider, and bought 25 percent of the company. Call-Net's long-distance service was renamed "Sprint Canada" and expanded to include landline and internet services. In 2005, Call-Net and Sprint Canada's 600,000 customers were acquired by Rogers Communications . In March 1993, Sprint merged with Chicago's Centel Corp. Centel remained in
4368-518: A subsidiary of T-Mobile until the Sprint brand officially discontinued in the beginning of August. Leadership, background, and stock changes happened immediately, with customer-side changes happening over time. The Sprint brand officially discontinued on August 2, 2020. Billing was already showing the T-Mobile brand, and on this date all retail, customer service, and all other company branding switched to
4524-649: A target without a clear line-of-sight path. Many microscopes use fiber-optic light sources to provide intense illumination of samples being studied. Optical fiber is also used in imaging optics. A coherent bundle of fibers is used, sometimes along with lenses, for a long, thin imaging device called an endoscope , which is used to view objects through a small hole. Medical endoscopes are used for minimally invasive exploratory or surgical procedures. Industrial endoscopes (see fiberscope or borescope ) are used for inspecting anything hard to reach, such as jet engine interiors. In some buildings, optical fibers route sunlight from
4680-411: A telephone network, the caller is connected to the person to whom they wish to talk by switches at various telephone exchanges . The switches form an electrical connection between the two users and the setting of these switches is determined electronically when the caller dials the number. Once the connection is made, the caller's voice is transformed to an electrical signal using a small microphone in
4836-524: A transparent cladding. Later that same year, Harold Hopkins and Narinder Singh Kapany at Imperial College in London succeeded in making image-transmitting bundles with over 10,000 fibers, and subsequently achieved image transmission through a 75 cm long bundle which combined several thousand fibers. The first practical fiber optic semi-flexible gastroscope was patented by Basil Hirschowitz , C. Wilbur Peters, and Lawrence E. Curtiss, researchers at
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4992-412: A version of the electrical telegraph that he unsuccessfully demonstrated on September 2, 1837. His code was an important advance over Wheatstone's signaling method. The first transatlantic telegraph cable was successfully completed on July 27, 1866, allowing transatlantic telecommunication for the first time. The conventional telephone was patented by Alexander Bell in 1876. Elisha Gray also filed
5148-468: Is a mechanical splice , where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors . The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics . The term was coined by Indian-American physicist Narinder Singh Kapany . Daniel Colladon and Jacques Babinet first demonstrated
5304-408: Is a global Tier 1 Internet service provider network, operating an 100G Internet backbone . Customers include large multinational corporations , government agencies, retail and restaurant chains, Tier 2 and Tier 3 ISPs, and medium-to-small businesses. SprintLink has physical presence in 155 countries, including the United States, Western Europe, East Asia, Australia, and India. The network wraps all
5460-453: Is a way of measuring the speed of light in a material. Light travels fastest in a vacuum , such as in outer space. The speed of light in vacuum is about 300,000 kilometers (186,000 miles) per second. The refractive index of a medium is calculated by dividing the speed of light in vacuum by the speed of light in that medium. The refractive index of vacuum is therefore 1, by definition. A typical single-mode fiber used for telecommunications has
5616-581: Is adapted from the French, because its written use was recorded in 1904 by the French engineer and novelist Édouard Estaunié . Communication was first used as an English word in the late 14th century. It comes from Old French comunicacion (14c., Modern French communication), from Latin communicationem (nominative communication), noun of action from past participle stem of communicare, "to share, divide out; communicate, impart, inform; join, unite, participate in," literally, "to make common", from communis". At
5772-411: Is bent towards the perpendicular ... When the ray passes from water to air it is bent from the perpendicular... If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface... The angle which marks the limit where total reflection begins is called the limiting angle of
5928-412: Is called multi-mode fiber , from the electromagnetic analysis (see below). In a step-index multi-mode fiber, rays of light are guided along the fiber core by total internal reflection. Rays that meet the core-cladding boundary at an angle (measured relative to a line normal to the boundary) greater than the critical angle for this boundary, are completely reflected. The critical angle is determined by
6084-671: Is called point-to-point communication because it occurs between a transmitter and a receiver. Telecommunication through radio broadcasts is called broadcast communication because it occurs between a powerful transmitter and numerous low-power but sensitive radio receivers. Telecommunications in which multiple transmitters and multiple receivers have been designed to cooperate and share the same physical channel are called multiplex systems . The sharing of physical channels using multiplexing often results in significant cost reduction. Multiplexed systems are laid out in telecommunication networks and multiplexed signals are switched at nodes through to
6240-418: Is called total internal reflection . This effect is used in optical fibers to confine light in the core. Most modern optical fiber is weakly guiding , meaning that the difference in refractive index between the core and the cladding is very small (typically less than 1%). Light travels through the fiber core, bouncing back and forth off the boundary between the core and cladding. Because the light must strike
6396-451: Is called (in the jargon of the field) " quadrature amplitude modulation " (QAM) that are used in high-capacity digital radio communication systems. Modulation can also be used to transmit the information of low-frequency analogue signals at higher frequencies. This is helpful because low-frequency analogue signals cannot be effectively transmitted over free space. Hence the information from a low-frequency analogue signal must be impressed into
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6552-434: Is commonly called "keying" —a term derived from the older use of Morse Code in telecommunications—and several keying techniques exist (these include phase-shift keying , frequency-shift keying , and amplitude-shift keying ). The " Bluetooth " system, for example, uses phase-shift keying to exchange information between various devices. In addition, there are combinations of phase-shift keying and amplitude-shift keying which
6708-794: Is converted from electricity to sound. Telecommunication systems are occasionally "duplex" (two-way systems) with a single box of electronics working as both the transmitter and a receiver, or a transceiver (e.g., a mobile phone ). The transmission electronics and the receiver electronics within a transceiver are quite independent of one another. This can be explained by the fact that radio transmitters contain power amplifiers that operate with electrical powers measured in watts or kilowatts, but radio receivers deal with radio powers measured in microwatts or nanowatts . Hence, transceivers have to be carefully designed and built to isolate their high-power circuitry and their low-power circuitry from each other to avoid interference. Telecommunication over fixed lines
6864-412: Is credited with creating the first major fiber optic network, having recognized it as a way to handle more calls and provide better quality sound. In 1972, United Utilities changed its name to United Telecommunications . In 1980, United Telecommunications began working on a 23,000 mile fiber optic network for long-distance calls. In 1989, this long-distance business became profitable for the company for
7020-481: Is degraded by undesirable noise . Commonly, the noise in a communication system can be expressed as adding or subtracting from the desirable signal via a random process . This form of noise is called additive noise , with the understanding that the noise can be negative or positive at different instances. Unless the additive noise disturbance exceeds a certain threshold, the information contained in digital signals will remain intact. Their resistance to noise represents
7176-507: Is designed for use in the near infrared . Multi-mode fiber, by comparison, is manufactured with core diameters as small as 50 micrometers and as large as hundreds of micrometers. Some special-purpose optical fiber is constructed with a non-cylindrical core or cladding layer, usually with an elliptical or rectangular cross-section. These include polarization-maintaining fiber used in fiber optic sensors and fiber designed to suppress whispering gallery mode propagation. Photonic-crystal fiber
7332-565: Is far less than in electrical copper cables, leading to long-haul fiber connections with repeater distances of 70–150 kilometers (43–93 mi). Two teams, led by David N. Payne of the University of Southampton and Emmanuel Desurvire at Bell Labs , developed the erbium-doped fiber amplifier , which reduced the cost of long-distance fiber systems by reducing or eliminating optical-electrical-optical repeaters, in 1986 and 1987 respectively. The emerging field of photonic crystals led to
7488-564: Is immune to electrical interference as there is no cross-talk between signals in different cables and no pickup of environmental noise. Information traveling inside the optical fiber is even immune to electromagnetic pulses generated by nuclear devices. Fiber cables do not conduct electricity, which makes fiber useful for protecting communications equipment in high voltage environments such as power generation facilities or applications prone to lightning strikes. The electrical isolation also prevents problems with ground loops . Because there
7644-418: Is important in fiber optic communication. This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a fusion splice is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique
7800-611: Is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide . Fibers that support many propagation paths or transverse modes are called multi-mode fibers , while those that support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft). Being able to join optical fibers with low loss
7956-405: Is made with a regular pattern of index variation (often in the form of cylindrical holes that run along the length of the fiber). Such fiber uses diffraction effects instead of or in addition to total internal reflection, to confine light to the fiber's core. The properties of the fiber can be tailored to a wide variety of applications. Attenuation in fiber optics, also known as transmission loss,
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#17327809019168112-412: Is monitored and analyzed for disturbances. This return signal is digitally processed to detect disturbances and trip an alarm if an intrusion has occurred. Optical fibers are widely used as components of optical chemical sensors and optical biosensors . Optical fiber can be used to transmit power using a photovoltaic cell to convert the light into electricity. While this method of power transmission
8268-439: Is no electricity in optical cables that could potentially generate sparks, they can be used in environments where explosive fumes are present. Wiretapping (in this case, fiber tapping ) is more difficult compared to electrical connections. Fiber cables are not targeted for metal theft . In contrast, copper cable systems use large amounts of copper and have been targeted since the 2000s commodities boom . The refractive index
8424-478: Is not as efficient as conventional ones, it is especially useful in situations where it is desirable not to have a metallic conductor as in the case of use near MRI machines, which produce strong magnetic fields. Other examples are for powering electronics in high-powered antenna elements and measurement devices used in high-voltage transmission equipment. Optical fibers are used as light guides in medical and other applications where bright light needs to be shone on
8580-609: Is self-evident in the case of online retailer Amazon.com but, according to academic Edward Lenert, even the conventional retailer Walmart has benefited from better telecommunication infrastructure compared to its competitors. In cities throughout the world, home owners use their telephones to order and arrange a variety of home services ranging from pizza deliveries to electricians. Even relatively poor communities have been noted to use telecommunication to their advantage. In Bangladesh 's Narsingdi District , isolated villagers use cellular phones to speak directly to wholesalers and arrange
8736-448: Is separated from its adjacent stations by 200 kHz, and the difference between 200 kHz and 180 kHz (20 kHz) is an engineering allowance for the imperfections in the communication system. In the example above, the "free space channel" has been divided into communications channels according to frequencies , and each channel is assigned a separate frequency bandwidth in which to broadcast radio waves. This system of dividing
8892-418: Is that they can, if required, provide distributed sensing over distances of up to one meter. Distributed acoustic sensing is one example of this. In contrast, highly localized measurements can be provided by integrating miniaturized sensing elements with the tip of the fiber. These can be implemented by various micro- and nanofabrication technologies, such that they do not exceed the microscopic boundary of
9048-422: Is the numerical aperture (NA) of the fiber. Fiber with a larger NA requires less precision to splice and work with than fiber with a smaller NA. The size of this acceptance cone is a function of the refractive index difference between the fiber's core and cladding. Single-mode fiber has a small NA. Fiber with large core diameter (greater than 10 micrometers) may be analyzed by geometrical optics . Such fiber
9204-449: Is the informational equivalent of two newspaper pages per person per day in 1986, and six entire newspapers per person per day by 2007. Given this growth, telecommunications play an increasingly important role in the world economy and the global telecommunications industry was about a $ 4.7 trillion sector in 2012. The service revenue of the global telecommunications industry was estimated to be $ 1.5 trillion in 2010, corresponding to 2.4% of
9360-474: Is the measurement of temperature inside jet engines by using a fiber to transmit radiation into a pyrometer outside the engine. Extrinsic sensors can be used in the same way to measure the internal temperature of electrical transformers , where the extreme electromagnetic fields present make other measurement techniques impossible. Extrinsic sensors measure vibration, rotation, displacement, velocity, acceleration, torque, and torsion. A solid-state version of
9516-428: Is the reduction in the intensity of the light signal as it travels through the transmission medium. Attenuation coefficients in fiber optics are usually expressed in units of dB/km. The medium is usually a fiber of silica glass that confines the incident light beam within. Attenuation is an important factor limiting the transmission of a digital signal across large distances. Thus, much research has gone into both limiting
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#17327809019169672-484: Is typical in deployed systems. Through the use of wavelength-division multiplexing (WDM), each fiber can carry many independent channels, each using a different wavelength of light. The net data rate (data rate without overhead bytes) per fiber is the per-channel data rate reduced by the forward error correction (FEC) overhead, multiplied by the number of channels (usually up to 80 in commercial dense WDM systems as of 2008 ). For short-distance applications, such as
9828-402: Is used as a medium for telecommunication and computer networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because infrared light propagates through the fiber with much lower attenuation compared to electricity in electrical cables. This allows long distances to be spanned with few repeaters . 10 or 40 Gbit/s
9984-773: The Nipkow disk by Paul Nipkow and thus became known as the mechanical television . It formed the basis of experimental broadcasts done by the British Broadcasting Corporation beginning on 30 September 1929. However, for most of the 20th century, televisions depended on the cathode ray tube invented by Karl Ferdinand Braun . The first version of such a television to show promise was produced by Philo Farnsworth and demonstrated to his family on 7 September 1927. After World War II, interrupted experiments resumed and television became an important home entertainment broadcast medium. The type of device known as
10140-437: The U.S. Federal Communications Commission (FCC), although a fax service (called SpeedFAX) was permitted. In the mid-1970s, SPC held a contest to select a new name for the company. The winning entry was "SPRINT", an acronym for "Southern Pacific Railroad Internal Networking Telephony". In 1982, it was announced that GTE Corp. had reached an agreement to buy SPC's long-distance telephone operation, including Sprint. The deal
10296-471: The University of Michigan , in 1956. In the process of developing the gastroscope, Curtiss produced the first glass-clad fibers; previous optical fibers had relied on air or impractical oils and waxes as the low-index cladding material. Kapany coined the term fiber optics after writing a 1960 article in Scientific American that introduced the topic to a wide audience. He subsequently wrote
10452-621: The contiguous United States under the Boost Mobile brand. The services are provided as an MVNO hosted on the Sprint-owned CDMA , EVDO , WiMAX , LTE , and LTE Advanced networks. Telecommunications Telecommunication , often used in its plural form or abbreviated as telecom , is the transmission of information with an immediacy comparable to face-to-face communication. As such, slow communications technologies like postal mail and pneumatic tubes are excluded from
10608-405: The gain medium of a fiber laser or optical amplifier . Rare-earth-doped optical fibers can be used to provide signal amplification by splicing a short section of doped fiber into a regular (undoped) optical fiber line. The doped fiber is optically pumped with a second laser wavelength that is coupled into the line in addition to the signal wave. Both wavelengths of light are transmitted through
10764-609: The local landline telephone business and spun those assets off into a new company named Embarq , which later became a part of Lumen Technologies under the CenturyLink brand, which remains one of the largest long-distance providers in the United States. Until 2005, the company was also known as the Sprint Corporation, but took the name Sprint Nextel Corporation when it merged with Nextel Communications and adopted its black and yellow color scheme, along with
10920-440: The spark gap transmitter for radio or mechanical computers for computing, it was the invention of the thermionic vacuum tube that made these technologies widespread and practical, leading to the creation of electronics . In the 1940s, the invention of semiconductor devices made it possible to produce solid-state devices, which are smaller, cheaper, and more efficient, reliable, and durable than thermionic tubes. Starting in
11076-705: The 1932 Plenipotentiary Telegraph Conference and the International Radiotelegraph Conference in Madrid, the two organizations merged to form the International Telecommunication Union (ITU). They defined telecommunication as "any telegraphic or telephonic communication of signs, signals, writing, facsimiles and sounds of any kind, by wire, wireless or other systems or processes of electric signaling or visual signaling (semaphores)." The definition
11232-497: The 1970s. In the 1960s, Paul Baran and, independently, Donald Davies started to investigate packet switching , a technology that sends a message in portions to its destination asynchronously without passing it through a centralized mainframe . A four-node network emerged on 5 December 1969, constituting the beginnings of the ARPANET , which by 1981 had grown to 213 nodes . ARPANET eventually merged with other networks to form
11388-566: The Brown Telephone Company and Southern Pacific Railroad . Brown Telephone Company was founded in 1899 by Cleyson Brown , to deploy the first telephone service to the rural area around Abilene, Kansas . The Browns installed their first long-distance circuit in 1900 and became an alternative to the Bell Telephone Company , the most popular telephone service at the time. In 1911, C. L. Brown consolidated
11544-634: The Brown Telephone Company with three other independents to form the United Telephone Company . C. L. Brown formed United Telephone and Electric (UT&E) in 1925. In 1939, at the end of the Great Depression , UT&E reorganized to form United Utilities . In 1964, Paul H. Henson became president of United Utilities; two years later, he was named chairman. When Henson began working at the company in 1959, it had 575,000 telephones in 15 states and revenues of $ 65 million. Henson
11700-566: The Chicago area and was renamed Sprint Cellular Co. In 1994, Sprint spun off their existing cellular operations as 360° Communications to comply with an FCC regulatory mandate. In 1998, 360 Communications was acquired by Alltel , which was in turn acquired by Verizon in 2009. In 1994, Sprint announces plans for a powerful new venture with three of the nation's major cable television companies, Tele-Communications Inc. (TCI), Comcast Corp. and Cox Cable . The four companies outline plans to build
11856-626: The Connected Officer program for the Los Angeles Police Department in partnership with Samsung , VMware , and Prodapt. Sprint wireline is also responsible for traditional telecommunications relay service (TRS), speech to speech relay service (STS), and captioned telephone service (CTS). Sprint is in the process of upgrading these services from a TDM network to an IP-based network Sprint Corporation offered postpaid wireless voice and data services primarily under
12012-466: The ITU was able to compile an index that measures the overall ability of citizens to access and use information and communication technologies. Using this measure, Sweden, Denmark and Iceland received the highest ranking while the African countries Niger , Burkina Faso and Mali received the lowest. Telecommunication has played a significant role in social relationships. Nevertheless, devices like
12168-744: The Internet. While Internet development was a focus of the Internet Engineering Task Force (IETF) who published a series of Request for Comments documents, other networking advancements occurred in industrial laboratories , such as the local area network (LAN) developments of Ethernet (1983), Token Ring (1984) and Star network topology. The effective capacity to exchange information worldwide through two-way telecommunication networks grew from 281 petabytes (PB) of optimally compressed information in 1986 to 471 PB in 1993 to 2.2 exabytes (EB) in 2000 to 65 EB in 2007. This
12324-561: The Sprint brand. The Sprint Prepaid Group was a division of the company formed in May 2010 that is responsible for the operations of Sprint's pre-pay subsidiaries. SPG's branded products and services are sold via web and available at retailers nationwide, including Best Buy , Walmart , Target and other independent dealers. Boost Worldwide, Inc. was a wholly owned subsidiary of Sprint that provides nationwide, prepaid wireless voice, messaging and broadband data products and services to customers in
12480-444: The T-Mobile brand. New rate plans were also introduced as well for all new and existing customers from both companies, though all will be grandfathered into their current plan for at least 3 years should they choose not to switch to a new T-Mobile plan. Customers with Sprint accounts were fully migrated to T-Mobile in the summer of 2023 officially discontinuing the Sprint brand. The Sprint Corporation traces its origins to two companies,
12636-441: The U.S. mobile phone industry, respectively. Sprint shareholders approved the merger on July 13, 2005. The merger deal was approved by the U.S. Federal Communications Commission (FCC) and U.S. Department of Justice on August 3, 2005. Sprint Nextel was formed on August 13, 2005, when the deal was completed. Sprint and Nextel faced opposition to the merger, mostly from regional affiliates that provided wireless services on behalf of
12792-506: The United Kingdom had used the service to coordinate social arrangements and 42% to flirt. In cultural terms, telecommunication has increased the public's ability to access music and film. With television, people can watch films they have not seen before in their own home without having to travel to the video store or cinema. With radio and the Internet, people can listen to music they have not heard before without having to travel to
12948-734: The United States was spent on media that depend upon telecommunication. Many countries have enacted legislation which conforms to the International Telecommunication Regulations established by the International Telecommunication Union (ITU), which is the "leading UN agency for information and communication technology issues". In 1947, at the Atlantic City Conference, the ITU decided to "afford international protection to all frequencies registered in
13104-564: The attenuation in fibers available at the time was caused by impurities that could be removed, rather than by fundamental physical effects such as scattering. They correctly and systematically theorized the light-loss properties for optical fiber and pointed out the right material to use for such fibers— silica glass with high purity. This discovery earned Kao the Nobel Prize in Physics in 2009. The crucial attenuation limit of 20 dB/km
13260-416: The boundary with an angle greater than the critical angle, only light that enters the fiber within a certain range of angles can travel down the fiber without leaking out. This range of angles is called the acceptance cone of the fiber. There is a maximum angle from the fiber axis at which light may enter the fiber so that it will propagate, or travel, in the core of the fiber. The sine of this maximum angle
13416-850: The caller's handset . This electrical signal is then sent through the network to the user at the other end where it is transformed back into sound by a small speaker in that person's handset. Fiber optic 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 find wide usage in fiber-optic communications , where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss and are immune to electromagnetic interference . Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in
13572-457: The cameras had to be supervised by someone with an appropriate security clearance. Charles K. Kao and George A. Hockham of the British company Standard Telephones and Cables (STC) were the first to promote the idea that the attenuation in optical fibers could be reduced below 20 decibels per kilometer (dB/km), making fibers a practical communication medium, in 1965. They proposed that
13728-416: The case of a fiberscope . Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers . Glass optical fibers are typically made by drawing , while plastic fibers can be made either by drawing or by extrusion . Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction . Light
13884-648: The companies. These regional affiliates felt that the new company would hinder competition. On September 1, 2005, Sprint Nextel combined plan offerings of its Sprint and Nextel brands to bring uniformity across the company's offerings. Nextel has licensed its identity to NII Holdings, Inc. , of which Sprint Nextel owned 18%. NII has used the Nextel brand to set up networks in many Latin American countries. Following Sprint's purchase of Nextel, Nextel sold all of its investment in NII Holdings. The integration process
14040-683: The company began to offer wireless service under the Sprint Spectrum brand in the Baltimore-Washington metropolitan area . This was the first commercial Personal Communications Service (PCS) network in the United States. Although the Sprint PCS service was CDMA , the original Washington-area network used GSM . Eventually, Sprint launched its new nationwide CDMA network, then in 1999 sold the decommissioned GSM infrastructure to Omnipoint which re-launched in May 2000. Omnipoint
14196-476: The company immediately after the merger closed. Tim Donahue, the Nextel CEO, stayed on as executive chairman, but ceded decision-making authority to Gary D. Forsee . Tom Kelly, COO of Nextel, took an interim staff position as Chief Strategy Officer. Two years after the merger, only a few key Nextel executives remained, with many former Nextel middle- and upper-level managers having left, citing reasons including
14352-549: The company to 80%. On November 7, 2012, Sprint Nextel announced the acquisition of 20 MHz of spectrum and 585,000 customers from U.S. Cellular in Chicago, St. Louis, central Illinois and three other Midwest markets. The deal was expected to close in mid-2013. Prior to July 9, 2013, Sprint Nextel only owned a 50.8% equity interest in Clearwire Corporation ; On December 17, 2012, Sprint Nextel agreed to pay US$ 2.97 per share, US$ 2.2 billion in total, to purchase
14508-521: The company was purchased by the Japanese telecommunications company SoftBank Group . Sprint used CDMA , EvDO and 4G LTE networks, and formerly operated iDEN , WiMAX , and 5G NR networks. Sprint was incorporated in Kansas. Sprint traced its origins to the Brown Telephone Company, which was founded in 1899 to bring telephone service to the rural area around Abilene , Kansas . In 2006, Sprint left
14664-546: The company. United Telecom announced it would complete its acquisition of US Sprint on April 18, 1990. United Telecom later officially changed its name to Sprint Corporation to capitalize on its brand recognition. Sprint Corporation entered the Canadian market in the early 1990s as a reseller of bulk long-distance telephone lines that it bought from domestic companies. Under Canadian foreign ownership regulations, Sprint could not open its own network. In 1993, Sprint entered into
14820-407: The core-cladding boundary. The resulting curved paths reduce multi-path dispersion because high-angle rays pass more through the lower-index periphery of the core, rather than the high-index center. The index profile is chosen to minimize the difference in axial propagation speeds of the various rays in the fiber. This ideal index profile is very close to a parabolic relationship between the index and
14976-437: The correct destination terminal receiver. Communications can be encoded as analogue or digital signals , which may in turn be carried by analogue or digital communication systems. Analogue signals vary continuously with respect to the information, while digital signals encode information as a set of discrete values (e.g., a set of ones and zeroes). During propagation and reception, information contained in analogue signals
15132-487: The deal, the company entered into a partnership with Sprint to serve as co-tenants in 1,435 of its locations, beginning on April 10, 2015. Roughly a third of the retail space in each location is dedicated to Sprint products and services, and the stores will ultimately adopt Sprint as their primary brand in place of RadioShack. Sprint stated that this deal would increase the company's retail footprint by more than double. On January 23, 2017, Sprint announced that they were buying
15288-500: The definition. Many transmission media have been used for telecommunications throughout history, from smoke signals , beacons , semaphore telegraphs , signal flags , and optical heliographs to wires and empty space made to carry electromagnetic signals. These paths of transmission may be divided into communication channels for multiplexing , allowing for a single medium to transmit several concurrent communication sessions . Several methods of long-distance communication before
15444-442: The development in 1991 of photonic-crystal fiber , which guides light by diffraction from a periodic structure, rather than by total internal reflection. The first photonic crystal fibers became commercially available in 2000. Photonic crystal fibers can carry higher power than conventional fibers and their wavelength-dependent properties can be manipulated to improve performance. These fibers can have hollow cores. Optical fiber
15600-519: The development of optical fibre. The Internet , a technology independent of any given medium, has provided global access to services for individual users and further reduced location and time limitations on communications. Telecommunication is a compound noun of the Greek prefix tele- (τῆλε), meaning distant , far off , or afar , and the Latin verb communicare , meaning to share . Its modern use
15756-537: The device—from the cathode to the anode. Adding one or more control grids within the tube enables the current between the cathode and anode to be controlled by the voltage on the grid or grids. These devices became a key component of electronic circuits for the first half of the 20th century and were crucial to the development of radio, television, radar, sound recording and reproduction , long-distance telephone networks, and analogue and early digital computers . While some applications had used earlier technologies such as
15912-467: The difference in the index of refraction between the core and cladding materials. Rays that meet the boundary at a low angle are refracted from the core into the cladding where they terminate. The critical angle determines the acceptance angle of the fiber, often reported as a numerical aperture . A high numerical aperture allows light to propagate down the fiber in rays both close to the axis and at various angles, allowing efficient coupling of light into
16068-445: The distance from the axis. Fiber with a core diameter less than about ten times the wavelength of the propagating light cannot be modeled using geometric optics. Instead, it must be analyzed as an electromagnetic waveguide structure, according to Maxwell's equations as reduced to the electromagnetic wave equation . As an optical waveguide, the fiber supports one or more confined transverse modes by which light can propagate along
16224-621: The doped fiber, which transfers energy from the second pump wavelength to the signal wave. The process that causes the amplification is stimulated emission . Optical fiber is also widely exploited as a nonlinear medium. The glass medium supports a host of nonlinear optical interactions, and the long interaction lengths possible in fiber facilitate a variety of phenomena, which are harnessed for applications and fundamental investigation. Conversely, fiber nonlinearity can have deleterious effects on optical signals, and measures are often required to minimize such unwanted effects. Optical fibers doped with
16380-632: The early 1970s, the company began looking for ways to use its existing communications lines for long-distance calling. This division of the business was named the Southern Pacific Communications Company. By the mid 1970s, SPC was beginning to take business away from AT&T , which held a monopoly at the time. A number of lawsuits between SPC and AT&T took place throughout the 1970s; the majority were decided in favor of increased competition. Prior attempts at offering long-distance voice services had not been approved by
16536-422: The electrical telegraph, the last commercial line was abandoned in 1880. On July 25, 1837, the first commercial electrical telegraph was demonstrated by English inventor Sir William Fothergill Cooke and English scientist Sir Charles Wheatstone . Both inventors viewed their device as "an improvement to the [existing] electromagnetic telegraph" and not as a new device. Samuel Morse independently developed
16692-403: The expense of increasing the channel bandwidth requirement. The term "channel" has two different meanings. In one meaning, a channel is the physical medium that carries a signal between the transmitter and the receiver. Examples of this include the atmosphere for sound communications, glass optical fibres for some kinds of optical communications , coaxial cables for communications by way of
16848-424: The fiber tip, allowing for such applications as insertion into blood vessels via hypodermic needle. Extrinsic fiber optic sensors use an optical fiber cable , normally a multi-mode one, to transmit modulated light from either a non-fiber optical sensor—or an electronic sensor connected to an optical transmitter. A major benefit of extrinsic sensors is their ability to reach otherwise inaccessible places. An example
17004-404: The fiber. Fiber supporting only one mode is called single-mode . The waveguide analysis shows that the light energy in the fiber is not completely confined in the core. Instead, especially in single-mode fibers, a significant fraction of the energy in the bound mode travels in the cladding as an evanescent wave . The most common type of single-mode fiber has a core diameter of 8–10 micrometers and
17160-438: The fiber. However, this high numerical aperture increases the amount of dispersion as rays at different angles have different path lengths and therefore take different amounts of time to traverse the fiber. In graded-index fiber, the index of refraction in the core decreases continuously between the axis and the cladding. This causes light rays to bend smoothly as they approach the cladding, rather than reflecting abruptly from
17316-493: The first book about the new field. The first working fiber-optic data transmission system was demonstrated by German physicist Manfred Börner at Telefunken Research Labs in Ulm in 1965, followed by the first patent application for this technology in 1966. In 1968, NASA used fiber optics in the television cameras that were sent to the moon. At the time, the use in the cameras was classified confidential , and employees handling
17472-403: The first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi , who won the 1909 Nobel Prize in Physics . Other early pioneers in electrical and electronic telecommunications include co-inventors of the telegraph Charles Wheatstone and Samuel Morse , numerous inventors and developers of
17628-558: The first time. In 1990, Henson retired from United Telecommunications; by this time the company's revenues had grown to $ 8 billion. Sprint also traces its roots back to the Southern Pacific Railroad (SPR), which was founded in the 1860s as a subsidiary of the Southern Pacific Company (SPC). The company operated thousands of miles of track as well as telegraph wire that ran along those tracks. In
17784-510: The guiding of light by refraction, the principle that makes fiber optics possible, in Paris in the early 1840s. John Tyndall included a demonstration of it in his public lectures in London , 12 years later. Tyndall also wrote about the property of total internal reflection in an introductory book about the nature of light in 1870: When the light passes from air into water, the refracted ray
17940-469: The gyroscope, using the interference of light, has been developed. The fiber optic gyroscope (FOG) has no moving parts and exploits the Sagnac effect to detect mechanical rotation. Common uses for fiber optic sensors include advanced intrusion detection security systems . The light is transmitted along a fiber optic sensor cable placed on a fence, pipeline, or communication cabling, and the returned signal
18096-431: The importance of social conversations and staying connected to family and friends. Since then the role that telecommunications has played in social relations has become increasingly important. In recent years, the popularity of social networking sites has increased dramatically. These sites allow users to communicate with each other as well as post photographs, events and profiles for others to see. The profiles can list
18252-550: The largest corporate merger in history at the time. However, due to pressure from the United States Department of Justice and the European Union on concerns of it creating a monopoly, the deal did not go through. In 1999, Sprint began recombining its local telecom, long-distance, wireline, and wireless business units into a new company, in an initiative known internally as "One Sprint". In April 2004,
18408-552: The management of telecommunication and broadcasting. The history of broadcasting discusses some debates in relation to balancing conventional communication such as printing and telecommunication such as radio broadcasting. The onset of World War II brought on the first explosion of international broadcasting propaganda. Countries, their governments, insurgents, terrorists, and militiamen have all used telecommunication and broadcasting techniques to promote propaganda. Patriotic propaganda for political movements and colonization started
18564-567: The medium into channels according to frequency is called " frequency-division multiplexing ". Another term for the same concept is " wavelength-division multiplexing ", which is more commonly used in optical communications when multiple transmitters share the same physical medium. Another way of dividing a communications medium into channels is to allocate each sender a recurring segment of time (a "time slot", for example, 20 milliseconds out of each second), and to allow each sender to send messages only within its own time slot. This method of dividing
18720-414: The medium into communication channels is called " time-division multiplexing " ( TDM ), and is used in optical fibre communication. Some radio communication systems use TDM within an allocated FDM channel. Hence, these systems use a hybrid of TDM and FDM. The shaping of a signal to convey information is known as modulation . Modulation can be used to represent a digital message as an analogue waveform. This
18876-413: The medium. For water this angle is 48°27′, for flint glass it is 38°41′, while for a diamond it is 23°42′. In the late 19th century, a team of Viennese doctors guided light through bent glass rods to illuminate body cavities. Practical applications such as close internal illumination during dentistry followed, early in the twentieth century. Image transmission through tubes was demonstrated independently by
19032-416: The merged company might violate existing agreements or significantly undercut earnings to these affiliates. In order for Sprint Nextel to allay some of this opposition, they initiated discussions of either acquiring some of these affiliates or renegotiating existing agreements. In several cases, the newly formed company was forced to acquire affiliated companies in exchange for their dropping their opposition to
19188-642: The merger. Forsee said that the company would likely have to acquire all of its remaining affiliates. In 2005, Sprint Nextel acquired three of its ten wireless affiliates: US Unwired, acquired in August; Gulf Coast Wireless, acquired in October; and IWO Holdings, acquired in October. Alamosa PCS, which Sprint Nextel acquired on February 2, 2006, was the largest of its affiliate carriers. Other acquired affiliates include Ubiquitel, iPCS, Enterprise, and Northern. In 2021, after merging with Sprint in 2020, T-Mobile acquired
19344-742: The mid-1930s. In 1936, the BBC broadcast propaganda to the Arab World to partly counter similar broadcasts from Italy, which also had colonial interests in North Africa. Modern political debates in telecommunication include the reclassification of broadband Internet service as a telecommunications service (also called net neutrality ), regulation of phone spam , and expanding affordable broadband access. According to data collected by Gartner and Ars Technica sales of main consumer's telecommunication equipment worldwide in millions of units was: In
19500-596: The mid-1960s, thermionic tubes were replaced with the transistor . Thermionic tubes still have some applications for certain high-frequency amplifiers. On 11 September 1940, George Stibitz transmitted problems for his Complex Number Calculator in New York using a teletype and received the computed results back at Dartmouth College in New Hampshire . This configuration of a centralized computer ( mainframe ) with remote dumb terminals remained popular well into
19656-429: The modern era used sounds like coded drumbeats , the blowing of horns , and whistles . Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the telegraph , telephone , television , and radio . Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In
19812-452: The music store. Telecommunication has also transformed the way people receive their news. A 2006 survey (right table) of slightly more than 3,000 Americans by the non-profit Pew Internet and American Life Project in the United States the majority specified television or radio over newspapers. Telecommunication has had an equally significant impact on advertising. TNS Media Intelligence reported that in 2007, 58% of advertising expenditure in
19968-400: The neighbourhood of 94.5 MHz (megahertz) while another radio station can simultaneously broadcast radio waves at frequencies in the neighbourhood of 96.1 MHz. Each radio station would transmit radio waves over a frequency bandwidth of about 180 kHz (kilohertz), centred at frequencies such as the above, which are called the "carrier frequencies" . Each station in this example
20124-513: The portion of Clearwire shares that Sprint Nextel did not already own. On June 20, 2013, Sprint Nextel increased its offer to $ 5 per share, the transaction was approved by regulators on July 5, 2013, and closed on July 9, 2013, and Sprint Nextel became the complete owner of Clearwire and its assets. On March 31, 2015, the U.S. bankruptcy court approved a $ 160 million takeover of electronics store chain RadioShack by Standard General . As part of
20280-515: The presence or absence of an atmosphere between the two. Radio waves travel through a perfect vacuum just as easily as they travel through air, fog, clouds, or any other kind of gas. The other meaning of the term "channel" in telecommunications is seen in the phrase communications channel , which is a subdivision of a transmission medium so that it can be used to send multiple streams of information simultaneously. For example, one radio station can broadcast radio waves into free space at frequencies in
20436-416: The radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. In the 1930s, Heinrich Lamm showed that one could transmit images through a bundle of unclad optical fibers and used it for internal medical examinations, but his work was largely forgotten. In 1953, Dutch scientist Bram van Heel first demonstrated image transmission through bundles of optical fibers with
20592-709: The relationship as causal. Because of the economic benefits of good telecommunication infrastructure, there is increasing worry about the inequitable access to telecommunication services amongst various countries of the world—this is known as the digital divide . A 2003 survey by the International Telecommunication Union (ITU) revealed that roughly a third of countries have fewer than one mobile subscription for every 20 people and one-third of countries have fewer than one land-line telephone subscription for every 20 people. In terms of Internet access, roughly half of all countries have fewer than one out of 20 people with Internet access. From this information, as well as educational data,
20748-582: The remaining two of Sprint's original ten affiliates, Shentel and Swiftel. Below are companies which Sprint Corporation has acquired: After the Sprint-Nextel merger, the company maintained an executive headquarters in Reston, Virginia and operational headquarters in Overland Park, Kansas . Sprint CEO Dan Hesse recognized that having two headquarters was not helping the merger effort, sent
20904-516: The road clear for SoftBank to acquire the company. The United States Federal Communications Commission approved SoftBank's acquisition of a stake in Sprint. The FCC's acting chairwoman Mignon Clyburn and commissioner Ajit Pai both gave statements vociferously supporting the acquisition, saying the deal "serve[s] the public interest". The acquisition was completed on July 10, 2013. On August 6, 2013, SoftBank purchased approximately 2% more shares of Sprint Corporation, increasing its ownership stake in
21060-431: The roof to other parts of the building (see nonimaging optics ). Optical-fiber lamps are used for illumination in decorative applications, including signs , art , toys and artificial Christmas trees . Optical fiber is an intrinsic part of the light-transmitting concrete building product LiTraCon . Optical fiber can also be used in structural health monitoring . This type of sensor can detect stresses that may have
21216-528: The separately traded wireless tracking stock PCS was absorbed into the New York Stock Exchange FON ticker symbol, Sprint's former ticker symbol (FON stood for "Fiber Optic Network", but was also a homophone of the word "phone"). This was challenged in many lawsuits by Sprint PCS shareholders who felt their stock was devalued because it was trading at the ratio of 1 share of PCS stock for 1/2 share of FON stock. The PCS shareholders claimed
21372-568: The speed of manufacture to over 50 meters per second, making optical fiber cables cheaper than traditional copper ones. These innovations ushered in the era of optical fiber telecommunication. The Italian research center CSELT worked with Corning to develop practical optical fiber cables, resulting in the first metropolitan fiber optic cable being deployed in Turin in 1977. CSELT also developed an early technique for splicing optical fibers, called Springroove. Attenuation in modern optical cables
21528-516: The telephone including Antonio Meucci , Philipp Reis , Elisha Gray and Alexander Graham Bell , inventors of radio Edwin Armstrong and Lee de Forest , as well as inventors of television like Vladimir K. Zworykin , John Logie Baird and Philo Farnsworth . Since the 1960s, the proliferation of digital technologies has meant that voice communications have gradually been supplemented by data. The physical limitations of metallic media prompted
21684-412: The telephone system were originally advertised with an emphasis on the practical dimensions of the device (such as the ability to conduct business or order home services) as opposed to the social dimensions. It was not until the late 1920s and 1930s that the social dimensions of the device became a prominent theme in telephone advertisements. New promotions started appealing to consumers' emotions, stressing
21840-631: The then-newly discovered phenomenon of radio waves , demonstrating, by 1901, that they could be transmitted across the Atlantic Ocean. This was the start of wireless telegraphy by radio. On 17 December 1902, a transmission from the Marconi station in Glace Bay, Nova Scotia, Canada , became the world's first radio message to cross the Atlantic from North America. In 1904, a commercial service
21996-408: The unbridgeable cultural difference between the two companies. In 2006, Sprint spun off its local telephone operations, including the former United Telephone companies and Centel , as Embarq . Sprint's acquisition of Nextel was a disaster from a fiscal standpoint in 2008, the company wrote down $ 29.7 billion of the $ 36 billion sum it had paid for Nextel in 2005, wiping out 80 percent of
22152-406: The value of Nextel at the time it had been acquired. The write down reflected the depreciation in Nextel's goodwill since the date of acquisition. Prior to their merger, Sprint and Nextel were dependent on a network of affiliated companies. Following the announcement of the merger agreement, some of these affiliates came forward with strong opposition to the Sprint-Nextel merger on the grounds that
22308-490: The voltages and electric currents in them, and free space for communications using visible light , infrared waves, ultraviolet light , and radio waves . Coaxial cable types are classified by RG type or "radio guide", terminology derived from World War II. The various RG designations are used to classify the specific signal transmission applications. This last channel is called the "free space channel". The sending of radio waves from one place to another has nothing to do with
22464-439: The wartime purposes of aircraft and land communication, radio navigation, and radar. Development of stereo FM broadcasting of radio began in the 1930s in the United States and the 1940s in the United Kingdom, displacing AM as the dominant commercial standard in the 1970s. On March 25, 1925, John Logie Baird demonstrated the transmission of moving pictures at the London department store Selfridges . Baird's device relied upon
22620-1130: The way around the world with buried fiber optics in the United States and Europe, and undersea fiber in the Pacific, Atlantic, and Indian Oceans. SprintLink is responsible for cable maintenance and administration in the TAT-14 Consortium . In 2008, Sprint was upgrading its SprintLink core to 100 Gbit/s lines to offer increased bandwidth. As of June 2012, Sprint picked Ciena for upgrading its Sprintlink core to 400 Gbit/s speeds. In 2007, Sprint launched Ethernet services over its IP/MPLS network to an initial 40-markets. Sprint later expanded their Ethernet services to 65 markets in September 2011. Sprint then launched Ethernet over copper and Ethernet over DOCSIS in 2016 to complement its Fiber Ethernet offerings. Sprint offers its enterprise customers managed web-based services through its Sprint Web Services program. It allows enterprise customers to create managed web-based applications In 2015, Sprint powered
22776-418: The world's gross domestic product (GDP). Modern telecommunication is founded on a series of key concepts that experienced progressive development and refinement in a period of well over a century: Telecommunication technologies may primarily be divided into wired and wireless methods. Overall, a basic telecommunication system consists of three main parts that are always present in some form or another: In
22932-637: The wrong message to employees and contributed to the post-merger cultural clash. To resolve the problem, Hesse decided to consolidate all headquarters operations in the Sprint World Headquarters Campus located in Overland Park, Kansas , a suburb in the Kansas City metropolitan area . On October 14, 2012, the Japanese telecommunications company SoftBank announced it intended to purchase 70% of Sprint Nextel Corporation for $ 20.1 billion. SoftBank stated that Sprint will remain
23088-403: Was difficult due to disparate network technologies. Sprint tried to address this with the advent of PowerSource phones. These phones routed voice call and data services over Sprint's PCS spectrum while maintaining DirectConnect services over 800 MHz spectrum. However, this was not sufficient in coverage, due to the inability to roam on a non-PCS spectrum. Top Nextel Executives began leaving
23244-490: Was during the Spanish Armada , when a beacon chain relayed a signal from Plymouth to London . In 1792, Claude Chappe , a French engineer, built the first fixed visual telegraphy system (or semaphore line ) between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres (six to nineteen miles). As a result of competition from
23400-407: Was established to transmit nightly news summaries to subscribing ships, which incorporated them into their onboard newspapers. World War I accelerated the development of radio for military communications . After the war, commercial radio AM broadcasting began in the 1920s and became an important mass medium for entertainment and news. World War II again accelerated the development of radio for
23556-675: Was first achieved in 1970 by researchers Robert D. Maurer , Donald Keck , Peter C. Schultz , and Frank Zimar working for American glass maker Corning Glass Works . They demonstrated a fiber with 17 dB/km attenuation by doping silica glass with titanium . A few years later they produced a fiber with only 4 dB/km attenuation using germanium dioxide as the core dopant. In 1981, General Electric produced fused quartz ingots that could be drawn into strands 25 miles (40 km) long. Initially, high-quality optical fibers could only be manufactured at 2 meters per second. Chemical engineer Thomas Mensah joined Corning in 1983 and increased
23712-429: Was later acquired by VoiceStream Wireless, which like Sprint would eventually be acquired by T-Mobile. In September 1996, Sprint announced a deal with RadioShack , and in 1997, Sprint stores opened at RadioShack to offer communications services and products across the United States. On October 5, 1999, Sprint and MCI WorldCom announced a $ 129 billion merger agreement between the two companies. The deal would have been
23868-529: Was later finalized in 1983. In 1986, GTE Sprint merged with the United Telecommunications Inc. property, US Telecom. The joint venture was to be co-owned by GTE and United Telecom named US Sprint Communications. The new entity also included communications firm GTE Telenet, and United Telecom Data communications Co., (formerly known as Uninet). In 1988, GTE sold more of Sprint to United Telecom, giving United Telecom operational control of
24024-471: Was later reconfirmed, according to Article 1.3 of the ITU Radio Regulations , which defined it as "Any transmission , emission or reception of signs, signals, writings, images and sounds or intelligence of any nature by wire , radio, optical, or other electromagnetic systems". Homing pigeons have been used throughout history by different cultures. Pigeon post had Persian roots and
24180-676: Was later used by the Romans to aid their military. Frontinus claimed Julius Caesar used pigeons as messengers in his conquest of Gaul . The Greeks also conveyed the names of the victors at the Olympic Games to various cities using homing pigeons. In the early 19th century, the Dutch government used the system in Java and Sumatra . And in 1849, Paul Julius Reuter started a pigeon service to fly stock prices between Aachen and Brussels ,
24336-486: Was of little practical value because it relied on the electrophonic effect requiring users to place the receiver in their mouths to "hear". The first commercial telephone services were set up by the Bell Telephone Company in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. In 1894, Italian inventor Guglielmo Marconi began developing a wireless communication using
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