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Mobile Telecommunications
Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur. Mobile phones connect to a terrestrial cellular network of base stations (cell sites), whereas satellite phones connect to orbiting satellites. Both networks are interconnected to the public switched telephone network (PSTN) to allow any phone in the world to be dialed. In 2010 there were estimated to be five billion mobile cellular subscriptions in the world. History According to internal memos, American Telephone & Telegraph discussed developing a wireless phone in 1915, but were afraid that deployment of the technology could undermine its monopoly on wired service in the U.S. Public mobile phone systems were first introduced in the years after the Second World War and made use of technology developed before and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telstra Mobile Phone Tower
Telstra Group Limited is an Australian telecommunications company that builds and operates telecommunications networks and markets voice, mobile, internet access, pay television and other products and services. It is a member of the S&P/ASX 20 and Australia's largest telecommunications company by market share. Telstra is the largest wireless carrier in Australia, with 18.8 million subscribers as of 2020. Telstra has a long history in Australia, originating together with Australia Post as the Postmaster-General's Department upon federation in 1901. Telstra has transitioned from a state-owned enterprise to a fully privatised company and has recently focused on diversified products and emerging technologies. History Australia's telecommunications services were originally controlled by the Postmaster-General's Department (PMG), formed in 1901 as a result of Australian Federation. Prior to 1901, telecommunications were administered by each colony. On 1 July 1975, separat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Securicor
Securicor plc was one of the United Kingdom's largest security businesses. It was once a constituent of the FTSE 100 Index but merged with Group 4 Falck in 2004. History The Company was founded by Edward Shortt, a former Liberal Cabinet Minister, in 1935 as ''Nightwatch Services'':Group 4's Danes to swoop on Securicor The Times, 1 February 2004 its guards rode bicycles and wore old police uniforms. However, in 1939 it was taken over by Lord Willingdon and Henry Tiarks who developed it into a leading security business. It changed its name to ''Security Corps'' in 1951 and shortened ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Information Theory
Information theory is the scientific study of the quantification, storage, and communication of information. The field was originally established by the works of Harry Nyquist and Ralph Hartley, in the 1920s, and Claude Shannon in the 1940s. The field is at the intersection of probability theory, statistics, computer science, statistical mechanics, information engineering, and electrical engineering. A key measure in information theory is entropy. Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process. For example, identifying the outcome of a fair coin flip (with two equally likely outcomes) provides less information (lower entropy) than specifying the outcome from a roll of a die (with six equally likely outcomes). Some other important measures in information theory are mutual information, channel capacity, error exponents, and relative entropy. Important sub-fields of information theory include s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large-scale Integration
An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Transistor count, Large numbers of tiny MOSFETs (metal–oxide–semiconductor field-effect transistors) integrate into a small chip. This results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete electronic components. The IC's mass production capability, reliability, and building-block approach to integrated circuit design has ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones and other home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs such as mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of National Inventors Hall Of Fame Inductees
The National Inventors Hall of Fame (NIHF) inductees includes over 600 inventors spanning three centuries of lifetimes. John Fitch was the earliest born inventor inducted into the NIHF (1743), while Barrett Comiskey is currently the most recently born (1975). Key Inductees References External links The official website of the National Inventors Hall of Fame {{DEFAULTSORT:National Inventors Hall of Fame inductees Awards established in 1973 Lists of inventors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MTD (mobile Network)
MTD (Swedish abbreviation for ''Mobiltelefonisystem D'', or ''Mobile telephony system D'') was a manual mobile phone system for the 450 MHz frequency band. It was introduced in 1971 in Sweden, and lasted until 1987, when it was made obsolete by the NMT automatic service. The MTD network had 20,000 users at its peak, with 700 people employed as phone operators. MTD was also implemented in Denmark and in Norway (from 1976), which allowed roaming within the Scandinavian countries. MTA In Sweden, the first mobile phone system was MTA (for ''Mobiltelefonisystem A''), which was introduced in 1956, and lasted until 1967. It was a 160 MHz system available in Stockholm and Gothenburg, with 125 total subscribers. The second system, MTB (for ''Mobiltelefonisystem B''), had transistorized mobile sets, was introduced in 1962, and lasted until 1983. It operated in the 76–77.5 and 81–82.5 MHz bands, was also available in Malmö, and had around 600 subscribers. OLT In Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by multinational company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. Researchers working at Bell Laboratories are credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B, C, C++, S, SNOBOL, AWK, AMPL, and others. Nine Nobel Prizes have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telephone conglomerate. In the late 19th century, the laboratory began as the Western Electric Engineering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Access Communication System
Total Access Communication System (TACS) and ETACS are variants of Advanced Mobile Phone System (AMPS) which were announced as the choice for the first two UK national cellular systems in February 1983, less than a year after the UK government announced the T&Cs for the two competing mobile phone networks in June 1982. This 1G technology is now obsolete. History Vodafone (known then as Racal-Vodafone) opted for a £30 million turnkey contract from Ericsson (ERA) to design, build and set up its initial network of 100 base station sites. Cellnet (then known Telecom Securicor Cellular Radio Ltd) used development labs in the facilities at General Electric (later made part of Motorola) based at Lynchburg, Virginia, United States. The reason Cellnet used the General Electric labs was because the AMPS system was already in development there, and the company had set up a production facility in readiness for AMPS production in 1985 which the Cellnet TACS was to share. In March 1984 de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Mobile Phone Service
Advanced Mobile Phone Service, Inc. was a subsidiary of AT&T prior to the Bell System Divestiture. Abbreviated AMPS, the company was created in 1978 to build and operate the new Advanced Mobile Phone System, also abbreviated AMPS. AMPS was developed by Bell Labs to replace older, severely limited radiophone services, such as IMTS. AMPS was one of the first modern cellular phone systems, which remained in operation until 2008. Service started in Chicago on October 13, 1983, and in the Washington, D.C., area December 1983. After divestiture, AMPS was divided among the 7 newly created Regional Holding Companies, now known as RBOCs: * NYNEX Mobile Communications * Bell Atlantic Mobile Systems * Ameritech Mobile Communications * BellSouth Mobility * PacTel Mobile Access * Southwestern Bell Mobile Systems * U S West NewVector Evolution of Successor Companies Through a series of mergers, acquisitions, and re-consolidation among the Baby Bells, these 7 original mobile operati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vodafone UK
Vodafone UK is a British telecommunications services provider, and a part of Vodafone Group Plc, the world's second-largest mobile phone company. Vodafone is the third-largest mobile network operator in the United Kingdom, with 16.9 million subscribers as of November 2021, after EE and O2, followed by Three. Vodafone has been the longest running network in the country since its first cellular network call was made in January 1985. The company's current slogan since 2020 is “Together we can”, replacing the previous slogan "The future is exciting. Ready?". The current branding and logo was created in 2017. History Mobile network In 1981, Racal Electronics Group won its bid for the private sector UK Cellular licence, and created Racal Telecomms Division. The same year, Racal formed a joint venture with Millicom named 'Racal Vodafone'. The Vodafone name was first unveiled on 22 March 1984. Vodafone made the first ever cellular telephone call in the United Kingdom on 1 J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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