1.
Switchboard operator
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Each pair of plugs was part of a cord circuit with a switch associated that let the operator participate in the call. Each jack had a light above it that lit when the receiver was lifted. Lines from the office were usually arranged along the bottom row. Switchboard operators are required to have very strong communication skills. Before the advent of automatic exchanges, an operators assistance was required for anything other than calling telephones across a party line. Callers spoke to an operator at a Central Office who then connected a cord to the circuit in order to complete the call. Being in complete control of the call, the operator was in a position to listen to private conversations, automatic, or Dial systems were developed in the 1920s to reduce labor costs as usage increased, and to ensure privacy to the customer. As phone systems became more sophisticated, less direct intervention by the operator was necessary to complete calls. As well as the people that were employed by the networks, operators were required at private branch exchanges to answer incoming telephone calls. Today, most large organizations have direct-dial extensions, smaller workplaces may have an automated system which allows callers to enter the extension of the called party, or a receptionist who answers calls and performs operator duties. Operators employed in healthcare settings have other duties, such as entry, greeting patients and visitors, taking messages, triaging. Experienced, well trained operators generally command a higher salary, in January 1878 George Willard Croy became the worlds first telephone operator when he started working for the Boston Telephone Dispatch company. Emma was hired by Alexander Graham Bell, and reportedly, could remember every number in the directory of the New England Telephone Company. Emma Nutt became the first female telephone operator on 1 September 1878 when she started working for the Boston Telephone Dispatch company, more women began to replace men within this sector of the workforce for several reasons. The companies observed that women were generally more courteous to callers, however, a contributing factor to women entering this workforce was because womens labour was cheap in comparison to mens. Specifically, women were paid from one half to one quarter of a mans salary, attendant console Operator assistance Private branch exchange Telephone operator Telephone switchboard Media related to Telephone operators at Wikimedia Commons
2.
Telecommunication
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Telecommunication is the transmission of signs, signals, messages, writings, images and sounds or intelligence of any nature by wire, radio, optical or other electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology and it is transmitted either electrically over physical media, such as cables, or via electromagnetic radiation. Such transmission paths are divided into communication channels which afford the advantages of multiplexing. The term is used in its plural form, telecommunications. Early means of communicating over a distance included visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, other examples of pre-modern long-distance communication included audio messages such as coded drumbeats, lung-blown horns, and loud whistles. Zworykin, John Logie Baird and Philo Farnsworth, the word telecommunication is a compound of the Greek prefix tele, meaning distant, far off, or afar, and the Latin communicare, meaning to share. Its modern use is adapted from the French, because its use was recorded in 1904 by the French engineer. Communication was first used as an English word in the late 14th century, 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 pass a single bit of information. One notable instance of their use was during the Spanish Armada, in 1792, Claude Chappe, a French engineer, built the first fixed visual telegraphy system between Lille and Paris. However semaphore suffered from the need for skilled operators and expensive towers at intervals of ten to thirty kilometres, as a result of competition from the electrical telegraph, the last commercial line was abandoned in 1880. Homing pigeons have occasionally used throughout history by different cultures. Pigeon post is thought to have Persians roots and was used by the Romans to aid their military, frontinus said that 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 service to fly stock prices between Aachen and Brussels, a service that operated for a year until the gap in the telegraph link was closed. Sir Charles Wheatstone and Sir William Fothergill Cooke invented the telegraph in 1837. Also, the first commercial electrical telegraph is purported to have constructed by Wheatstone and Cooke. Both inventors viewed their device as an improvement to the electromagnetic telegraph not as a new device, samuel Morse independently developed a version of the electrical telegraph that he unsuccessfully demonstrated on 2 September 1837
3.
Telephone call
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A telephone call is a connection over a telephone network between the called party and the calling party. The first telephone call was made on March 10,1876 by Alexander Graham Bell, Bell demonstrated his ability to talk with electricity by transmitting a call to his assistant, Thomas Watson. The first words transmitted were Mr Watson, come here and this event has been called Bells greatest success, as it demonstrated the first successful use of the telephone. Although it was his greatest success, he refused to have one in his own home because it was something he invented by mistake, the call may use land line, mobile phone, satellite phone or any combination thereof. When a telephone call has more than one called party it is referred to as a conference call, when two or more users of the network are sharing the same physical line, it is called a party line or Rural phone line. If the callers wireline phone is connected directly to the party, when the caller takes their telephone off-hook. This is called a hot line or ringdown, otherwise, the calling party is usually given a tone to indicate they should begin dialing the desired number. In some cases, if the party cannot dial calls directly. Calls may be placed through a public network provided by a telephone company or a private network called a PBX. In most cases a private network is connected to the network in order to allow PBX users to dial the outside world. Most telephone calls through the PSTN are set up using ISUP signalling messages or one of its variants between telephone exchanges to establish the end to end connection, calls through PBX networks are set up using QSIG, DPNSS or variants. Some types of calls are not charged, such as local calls dialed directly by a subscriber in Canada. In most other areas, all calls are charged a fee for the connection. Fees depend on the provider of the service, the type of service being used, in most circumstances, the calling party pays this fee. However, in circumstances such as a reverse charge or collect call. In some circumstances, the caller pays a flat charge for the telephone connection. The caller then rotary dials or presses buttons for the number needed to complete the call. The second phone makes a noise to alert its owner
4.
Bell System
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On December 31,1983, the system was broken up into independent companies by a U. S. Justice Department mandate. Ma Bell is also used to refer to the female voices behind recordings for the Bell System, Mary Moore, Jane Barbe. In 1877, the American Bell Telephone Company, named after Alexander Graham Bell, opened the first telephone exchange in New Haven, within a few years local exchange companies were established in every major city in the United States. In 1899, American Telephone & Telegraph acquired the assets of its parent, originally American Bell had created AT&T to provide long-distance calls between New York and Chicago and beyond. AT&T became the parent of American Bell, and thus the head of the Bell System, because regulatory and tax rules were leaner in New York than in Boston, after 1934, AT&T was regulated by the Federal Communication Commission. Receiving a U. S. patent for the invention of the telephone on March 7,1876, Alexander Graham Bell formed the Bell Telephone Company in 1877, on April 30,1907, Theodore Newton Vail returned as President of AT&T. Vail believed in the superiority of one system and AT&T adopted the slogan One Policy, One System. This would be the philosophy for the next 70 years. Under Vail, AT&T began buying up many of the telephone companies including Western Union telegraph. Anxious to avoid action from government antitrust suits, AT&T entered into an agreement known as the Kingsbury Commitment with the federal government. S. The Bell trademark pictured here was used from 1921 through 1939 by both the AT&T corporation and the regional operating corporations to co-brand themselves under a single Bell System trademark, the regional operating corporations name was placed where name of associated company appears in this template version of the trademark. Bell system telephones and related equipment were made by Western Electric, member telephone companies paid a fixed fraction of their revenues as a license fee to Bell Labs. As a result of this monopoly, by 1940 the Bell System effectively owned most telephone service in the United States, from local. This allowed Bell to prohibit their customers from connecting phones not made or sold by Bell to the system without paying fees, Northern Electric was spun off in 1956 by Western Electric, but AT&T did not spin off Bell Canada until 1975. The Bell Systems Caribbean regional operating companies were sold to the ITT Corporation, before 1956, the Bell Systems reach was truly gargantuan. The 1984 Bell System divestiture brought an end to the branded as the Bell System. The suit was settled on January 8,1982, superseding the former restrictions that AT&T and the DOJ had agreed upon in 1956. Currently, the word mark Bell, the logo, and other related trademarks, are held by each of the remaining Bell companies, namely AT&T, Verizon, CenturyLink, and Cincinnati Bell
5.
Business telephone system
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Business telephone systems are often broadly classified into key telephone systems, and private branch exchanges, but many hybrid systems exist. Technologically, private branch exchanges share lineage with central office telephone systems, with a key telephone system, a station user could control the connections directly using line buttons, which indicated the status of lines with built-in lamps. Key telephone systems are defined by arrangements with individual line selection buttons for each available telephone line. The earliest systems were known as wiring plans and simply consisted of sets, keys, lamps. Key was a Bell System term of art for a switching system such as the line-buttons on the phones associated with such systems. The wiring plans evolved into modular hardware building blocks with a variety of functionality, Key systems can be built using three principal architectures, electromechanical shared-control, electronic shared-control, or independent key sets. New installations of key systems have become less common, as hybrid systems and private branch exchanges of comparable size have similar cost. Before the advent of integrated circuits, key systems were typically composed of electromechanical components as were larger telephone switching systems. The systems marketed in North America as the 1A, 6A, 1A1, the 1A family of Western Electric Company key telephone units were introduced in the late 1930s and remained in use to the 1950s. 1A equipment was primitive and required at least two KTUs per line, one for line termination and one for station termination, the telephone instrument commonly used by 1A systems was the WECo 300-series telephone. Introduced in 1953, 1A1 key systems simplified wiring with a single KTU for both line and station termination, and increased the features available, as the 1A1 systems became commonplace, requirements for intercom features grew. The original intercom KTUs, WECo Model 207, were wired for a single link, that is. The WECo 6A dial intercom system provided two talk links and was installed as the dial intercom in a 1A1 or 1A2 key system. The 6A systems were complex, troublesome and expensive, and never became popular, the advent of 1A2 technology in the 1964 simplified key system set up and maintenance. These continued to be used throughout the 1980s, when the arrival of electronic key systems with their easier installation, two lesser-known key systems were used at airports for air traffic control communications, the 102 and 302 key systems. These were uniquely designed for communications between the air control tower and radar approach control or ground control approach, and included radio line connections. With the advent of LSI ICs, the architecture could be implemented much less expensively than was possible using relays. In addition, it was possible to eliminate the many-wire cabling, electronic shared-control systems led quickly to the modern hybrid telephone system, as the features of PBX and key system quickly merged
6.
Conceptual model
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A conceptual model is a representation of a system, made of the composition of concepts which are used to help people know, understand, or simulate a subject the model represents. Some models are physical objects, for example, a toy model which may be assembled, the term conceptual model may be used to refer to models which are formed after a conceptualization or generalization process. Conceptual models are often abstractions of things in the world whether physical or social. Semantics studies are relevant to various stages of formation and use as Semantics is basically about concepts. The term conceptual model is normal and it could mean a model of concept or it could mean a model that is conceptual. A distinction can be made between what models are and what models are models of, with the exception of iconic models, such as a scale model of Winchester Cathedral, most models are concepts. But they are, mostly, intended to be models of world states of affairs. The value of a model is directly proportional to how well it corresponds to a past, present, future. A model of a concept is different because in order to be a good model it need not have this real world correspondence. Conceptual models also range in terms of the scope of the matter that they are taken to represent. A model may, for instance, represent a single thing, whole classes of things, the variety and scope of conceptual models is due to then variety of purposes had by the people using them. Conceptual modeling is the activity of formally describing some aspects of the physical and social world around us for the purposes of understanding, a conceptual models primary objective is to convey the fundamental principles and basic functionality of the system which it represents. Also, a model must be developed in such a way as to provide an easily understood system interpretation for the models users. A conceptual model, when implemented properly, should satisfy four fundamental objectives, figure 1 below, depicts the role of the conceptual model in a typical system development scheme. It is clear if the conceptual model is not fully developed. These failures do occur in the industry and have linked to, lack of user input, incomplete or unclear requirements. Those weak links in the design and development process can be traced to improper execution of the fundamental objectives of conceptual modeling. The importance of conceptual modeling is evident when such systemic failures are mitigated by thorough system development, as systems have become increasingly complex, the role of conceptual modeling has dramatically expanded
7.
Invention of the telephone
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The invention of the telephone was the culmination of work done by many individuals, and involved an array of lawsuits founded upon the patent claims of several individuals and numerous companies. The concept of the dates back to the string telephone or lovers telephone that has been known for centuries. Sound waves are carried as mechanical vibrations along the string or wire from one diaphragm to the other. The classic example is the tin can telephone, a toy made by connecting the two ends of a string to the bottoms of two metal cans, paper cups or similar items. The essential idea of this toy was that a diaphragm can collect voice sounds from the air, as in the ear, gausss and Webers invention is purported to be the worlds first electromagnetic telegraph. In 1840, American Charles Grafton Page passed a current through a coil of wire placed between the poles of a horseshoe magnet. He observed that connecting and disconnecting the current caused a sound in the magnet. He called this effect galvanic music, innocenzo Manzetti considered the idea of a telephone as early as 1844, and may have made one in 1864, as an enhancement to an automaton built by him in 1849. Charles Bourseul was a French telegraph engineer who proposed the first design of a telephone in 1854. That is about the time that Meucci later claimed to have created his first attempt at the telephone in Italy. It is certain that, in a more or less distant future, I have made experiments in this direction, they are delicate and demand time and patience, but the approximations obtained promise a favourable result. The Reis transmitter was very difficult to the operate, since the position of the needle. Prior to 1947, the Reis device was tested by the British company Standard Telephones and Cables, the results also confirmed it could faintly transmit and receive speech. An early voice communicating device was invented around 1854 by Antonio Meucci, in 1871 Meucci filed a caveat at the US Patent Office. The first American demonstration of Meuccis invention took place in Staten Island, in the 1880s Meucci was credited with the early invention of inductive loading of telephone wires to increase long-distance signals. Unfortunately, serious burns from an accident, a lack of English, Meucci demonstrated some sort of instrument in 1849 in Havana, Cuba, however this may have been a variant of a string telephone that used wire. Meucci has been credited with invention of an anti-sidetone circuit. However, examination showed that his solution to sidetone was to two separate telephone circuits, and thus use twice as many transmission wires
8.
Hungary
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Hungary is a unitary parliamentary republic in Central Europe. With about 10 million inhabitants, Hungary is a member state of the European Union. The official language is Hungarian, which is the most widely spoken language in Europe. Hungarys capital and largest metropolis is Budapest, a significant economic hub, major urban areas include Debrecen, Szeged, Miskolc, Pécs and Győr. His great-grandson Stephen I ascended to the throne in 1000, converting the country to a Christian kingdom, by the 12th century, Hungary became a middle power within the Western world, reaching a golden age by the 15th century. Hungarys current borders were established in 1920 by the Treaty of Trianon after World War I, when the country lost 71% of its territory, 58% of its population, following the interwar period, Hungary joined the Axis Powers in World War II, suffering significant damage and casualties. Hungary became a state of the Soviet Union, which contributed to the establishment of a four-decade-long communist dictatorship. On 23 October 1989, Hungary became again a democratic parliamentary republic, in the 21st century, Hungary is a middle power and has the worlds 57th largest economy by nominal GDP, as well as the 58th largest by PPP, out of 188 countries measured by the IMF. As a substantial actor in several industrial and technological sectors, it is both the worlds 36th largest exporter and importer of goods, Hungary is a high-income economy with a very high standard of living. It keeps up a security and universal health care system. Hungary joined the European Union in 2004 and part of the Schengen Area since 2007, Hungary is a member of the United Nations, NATO, WTO, World Bank, the AIIB, the Council of Europe and Visegrád Group. Well known for its cultural history, Hungary has been contributed significantly to arts, music, literature, sports and science. Hungary is the 11th most popular country as a tourist destination in Europe and it is home to the largest thermal water cave system, the second largest thermal lake in the world, the largest lake in Central Europe, and the largest natural grasslands in Europe. The H in the name of Hungary is most likely due to historical associations with the Huns. The rest of the word comes from the Latinized form of Medieval Greek Oungroi, according to an explanation the Greek name was borrowed from Proto-Slavic Ǫgǔri, in turn borrowed from Oghur-Turkic Onogur. Onogur was the name for the tribes who later joined the Bulgar tribal confederacy that ruled the eastern parts of Hungary after the Avars. The Hungarians likely belonged to the Onogur tribal alliance and it is possible they became its ethnic majority. The Hungarian endonym is Magyarország, composed of magyar and ország, the word magyar is taken from the name of one of the seven major semi-nomadic Hungarian tribes, magyeri
9.
Thomas Edison
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Thomas Alva Edison was an American inventor and businessman, who has been described as Americas greatest inventor. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and the long-lasting, practical electric light bulb. Edison was an inventor, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France. Edisons inventions contributed to mass communication and, in particular, telecommunications and these included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures. His advanced work in these fields was an outgrowth of his career as a telegraph operator. Edison developed a system of generation and distribution to homes, businesses. His first power station was on Pearl Street in Manhattan, New York, Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. and Nancy Matthews Elliott. His father, the son of a Loyalist refugee, had moved as a boy with the family from Nova Scotia, settling in southwestern Ontario, in a known as Shewsbury, later Vienna. Samuel Jr. eventually fled Ontario because he took part in the unsuccessful Mackenzie Rebellion of 1837 and his father, Samuel Sr. had earlier fought in the War of 1812 as captain of the First Middlesex Regiment. By contrast, Samuel Jr. s struggle found him on the losing side, once across the border, he found his way to Milan, Ohio. His patrilineal family line was Dutch by way of New Jersey and his mother taught him at home. Much of his education came from reading R. G, parkers School of Natural Philosophy and The Cooper Union for the Advancement of Science and Art. Edison developed hearing problems at an early age, the cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. In his later years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, Edisons family moved to Port Huron, Michigan, after the railroad bypassed Milan in 1854 and business declined. Edison sold candy and newspapers on trains running from Port Huron to Detroit and he briefly worked as a telegraph operator in 1863 for the Grand Trunk Railway at Stratford, Ontario railway at age 16. He was held responsible for a near collision and he also studied qualitative analysis and conducted chemical experiments on the train until he left the job. Edison obtained the right to sell newspapers on the road, and, with the aid of four assistants, he set in type and printed the Grand Trunk Herald
10.
Bell Telephone Company
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The Bell Telephone Company was started on the basis of holding potentially valuable patents, principally Bells master telephone patent #174465. Theodore Vail then took over its operations at that point, becoming a figure in its rapid growth. The National Bell Telephone Company merged with American Speaking Telephone Company on March 20,1880, to form the American Bell Telephone Company, also of Boston, the American Bell Telephone Company evolved into the American Telephone & Telegraph Company, at times the worlds largest telephone company. The Bell Patent Association, was not an entity but a trusteeship. It was established verbally in 1874 to be the holders of the produced by Alexander Graham Bell. Hubbard later registered some of his shares with two family members. The verbal patent association agreement was formalized in a memorandum of agreement on February 27,1875, the patent associations assets became the foundational assets of the Bell Telephone Company. It then merged with the New England Telephone and Telegraph Company to form the National Bell Telephone Company, a little over a year later it was reorganized to become the American Bell Telephone Company. American Bells outstanding stock rose to 258,863 shares by May 1900, both Hubbards and Sanders roles in the newly born company were pivotal to its early survival and its eventual growth to become a corporate giant. Hubbards very early structuring of its service by leasing, instead of selling telephones, was critical to its success. Hubbard insisted that leasing was the option, even if it significantly raised the need for initial capital expenses. IBTCs first non-North American subsidiary was the Bell Telephone Manufacturing Company, established by Hubbard at Antwerp, Belgium, the Bell Systems Bell Telephone Company of Canada subsidiary, wholly owned by the National Bell, had been established two years earlier. AT&T President Frederick Fish later returned Bells single American Bell Telephone Company share to him as a memento after it had converted and canceled. He also remained a confident of Bell, who helped ensure the welfare of Sanders deaf son in his adulthood. Under Forbes leadership a new committee was created at its corporate level to reorganize. The company was recapitalized, with Vail continuing as its head of operations. After leaving the offices of what became the American Bell Telephone Company, Hubbard created the National Geographic Society as its president, ownership of American Bell was transferred to its own subsidiary, American Telephone & Telegraph Company on the second to last day of 1899. AT&T had been incorporated on April 17,1880 as American Bells long lines division to handle its long distance telecommunications, on January 1,1900, AT&T, a publicly traded corporation, owned the major assets of American Bell and thus became the head of the Bell System
11.
Boston
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Boston is the capital and most populous city of the Commonwealth of Massachusetts in the United States. Boston is also the seat of Suffolk County, although the county government was disbanded on July 1,1999. The city proper covers 48 square miles with a population of 667,137 in 2015, making it the largest city in New England. Alternately, as a Combined Statistical Area, this wider commuting region is home to some 8.1 million people, One of the oldest cities in the United States, Boston was founded on the Shawmut Peninsula in 1630 by Puritan settlers from England. It was the scene of several key events of the American Revolution, such as the Boston Massacre, the Boston Tea Party, the Battle of Bunker Hill, and the Siege of Boston. Upon U. S. independence from Great Britain, it continued to be an important port and manufacturing hub as well as a center for education, through land reclamation and municipal annexation, Boston has expanded beyond the original peninsula. Its rich history attracts many tourists, with Faneuil Hall alone drawing over 20 million visitors per year, Bostons many firsts include the United States first public school, Boston Latin School, first subway system, the Tremont Street Subway, and first public park, Boston Common. Bostons economic base also includes finance, professional and business services, biotechnology, information technology, the city has one of the highest costs of living in the United States as it has undergone gentrification, though it remains high on world livability rankings. Bostons early European settlers had first called the area Trimountaine but later renamed it Boston after Boston, Lincolnshire, England, the renaming on September 7,1630 was by Puritan colonists from England who had moved over from Charlestown earlier that year in quest of fresh water. Their settlement was limited to the Shawmut Peninsula, at that time surrounded by the Massachusetts Bay and Charles River. The peninsula is thought to have been inhabited as early as 5000 BC, in 1629, the Massachusetts Bay Colonys first governor John Winthrop led the signing of the Cambridge Agreement, a key founding document of the city. Puritan ethics and their focus on education influenced its early history, over the next 130 years, the city participated in four French and Indian Wars, until the British defeated the French and their Indian allies in North America. Boston was the largest town in British America until Philadelphia grew larger in the mid-18th century, Bostons harbor activity was significantly curtailed by the Embargo Act of 1807 and the War of 1812. Foreign trade returned after these hostilities, but Bostons merchants had found alternatives for their investments in the interim. Manufacturing became an important component of the economy, and the citys industrial manufacturing overtook international trade in economic importance by the mid-19th century. Boston remained one of the nations largest manufacturing centers until the early 20th century, a network of small rivers bordering the city and connecting it to the surrounding region facilitated shipment of goods and led to a proliferation of mills and factories. Later, a network of railroads furthered the regions industry. Boston was a port of the Atlantic triangular slave trade in the New England colonies
12.
Berlin
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Berlin is the capital and the largest city of Germany as well as one of its constituent 16 states. With a population of approximately 3.5 million, Berlin is the second most populous city proper, due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. Around one-third of the area is composed of forests, parks, gardens, rivers. Berlin in the 1920s was the third largest municipality in the world, following German reunification in 1990, Berlin once again became the capital of all-Germany. Berlin is a city of culture, politics, media. Its economy is based on high-tech firms and the sector, encompassing a diverse range of creative industries, research facilities, media corporations. Berlin serves as a hub for air and rail traffic and has a highly complex public transportation network. The metropolis is a popular tourist destination, significant industries also include IT, pharmaceuticals, biomedical engineering, clean tech, biotechnology, construction and electronics. Modern Berlin is home to world renowned universities, orchestras, museums and its urban setting has made it a sought-after location for international film productions. The city is known for its festivals, diverse architecture, nightlife, contemporary arts. Since 2000 Berlin has seen the emergence of a cosmopolitan entrepreneurial scene, the name Berlin has its roots in the language of West Slavic inhabitants of the area of todays Berlin, and may be related to the Old Polabian stem berl-/birl-. All German place names ending on -ow, -itz and -in, since the Ber- at the beginning sounds like the German word Bär, a bear appears in the coat of arms of the city. It is therefore a canting arm, the first written records of towns in the area of present-day Berlin date from the late 12th century. Spandau is first mentioned in 1197 and Köpenick in 1209, although these areas did not join Berlin until 1920, the central part of Berlin can be traced back to two towns. Cölln on the Fischerinsel is first mentioned in a 1237 document,1237 is considered the founding date of the city. The two towns over time formed close economic and social ties, and profited from the right on the two important trade routes Via Imperii and from Bruges to Novgorod. In 1307, they formed an alliance with a common external policy, in 1415 Frederick I became the elector of the Margraviate of Brandenburg, which he ruled until 1440. In 1443 Frederick II Irontooth started the construction of a new palace in the twin city Berlin-Cölln
13.
Heinrich von Stephan
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Heinrich von Stephan was a general post director for the German Empire who reorganized the German postal service. He was integral in the founding of the Universal Postal Union in 1874, Stephan was born in Stolp, Pomerania, in the Kingdom of Prussia. He began his career as a postal clerk in the service of the Prussian post in 1849. In 1866 he was put in charge by the Prussian government of federalizing the postal service that had long been run by the noble Thurn und Taxis family. In 1870 he was named director of services for the North German Confederation. When Stephan began his work as a worker, Germany was divided into 17 independent states. He worked early on to establish a uniform rate throughout Germany. He is also credited with having introduced the telephone to Germany, Stephan died in 1897 in Berlin, having made a profound impact on the standardization of mail service worldwide. He was also engaged in cultivating purely Germanic terminology for the field of telecommunication. The German-speaking afterworld thus gained terms such as Fernsprechapparat for telephone, Wertzeichen for stamp, postlagernd for poste restante and Anschrift for address. The word creations mandated by von Stephan in the 1870s gained circulation at post offices and among its workforce, thus at home people would say frankieren for putting stamps on a postcard or letter envelope among themselves, but switch to freimachen when at the post office. Or at home they would say Telefon in everyday speech, although the official term was Fernsprecher or Fernsprechapparat. Geschichte der Preussischen Post von ihrem Ursprunge bis auf die Gegenwart, nach amtl
14.
New Haven, Connecticut
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New Haven, in the U. S. state of Connecticut, is the principal municipality in Greater New Haven, which had a total population of 862,477 in 2010. It is located on New Haven Harbor on the shore of Long Island Sound in New Haven County, Connecticut. It is the second-largest city in Connecticut, with a population of 129,779 people as of the 2010 United States Census, according to a census of 1 July 2012, by the Census Bureau, the city had a population of 130,741. New Haven was founded in 1638 by English Puritans, and a year later eight streets were laid out in a four-by-four grid, the central common block is the New Haven Green, a 16-acre square, and the center of Downtown New Haven. The Green is now a National Historic Landmark and the Nine Square Plan is recognized by the American Planning Association as a National Planning Landmark, New Haven is the home of Yale University. The university is an part of the citys economy, being New Havens biggest taxpayer and employer. Health care, professional services, financial services, and retail trade also help to form a base for the city. The city served as co-capital of Connecticut from 1701 until 1873, New Haven has since billed itself as the Cultural Capital of Connecticut for its supply of established theaters, museums, and music venues. New Haven is also the birthplace of George W. Bush, New Haven had the first public tree planting program in America, producing a canopy of mature trees that gave New Haven the nickname The Elm City. The area was visited by Dutch explorer Adriaen Block in 1614. Dutch traders set up a trading system of beaver pelts with the local inhabitants, but trade was sporadic. In 1637 a small party of Puritans reconnoitered the New Haven harbor area, the Quinnipiacs, who were under attack by neighboring Pequots, sold their land to the settlers in return for protection. By 1640, the theocratic government and nine-square grid plan were in place. However, the north of New Haven remained Quinnipiac until 1678. The settlement became the headquarters of the New Haven Colony, at the time, the New Haven Colony was separate from the Connecticut Colony, which had been established to the north centering on Hartford. Economic disaster struck the colony in 1646, however, when the town sent its first fully loaded ship of goods back to England. This ship never reached the Old World, and its disappearance stymied New Havens development in the face of the rising power of Boston. In 1660, founder John Davenports wishes were fulfilled, and Hopkins School was founded in New Haven with money from the estate of Edward Hopkins, in 1661, the judges who had signed the death warrant of Charles I of England were pursued by Charles II
15.
Charles Jasper Glidden
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Charles Jasper Glidden was an American telephone pioneer, financier and supporter of the automobile in the United States. Charles Glidden, with his wife Lucy, were the first to circle the world in an automobile, Glidden was the adopted child of Nathaniel Glidden and Laura Clark. He came from a family that had arrived in America by 1664 and his professional career began at the age of 15. At 20, he was Branch Manager for the Atlantic-Pacific Telegraph Company and he recognized early the potential of the phone together and experimented together with Alexander Graham Bell with telephone connections over the telegraph lines. Glidden funded the construction of lines in Manchester, New Hampshire and was the first to recognize that the female voice was more suitable for the early telephones than the male. Accordingly, he hired women as telephone operators, the telephone exchange, which he had initiated, grew to a syndicate, which, amongst others, covered the U. S. states of Ohio, Minnesota, Arkansas and Texas. The first long-distance telephone connection was established on his initiative, on 10 July 1878, he married Lucy Emma Clegworth from Manchester, New Hampshire. Charles Glidden believed that the automobile was not just a toy for the rich and this required building confidence in the fledgling horseless carriage and a sound road system. In 1901 he sold his company to Bell and pursued these new goals as a private man and that same year, he and his wife made a successful trip to the Arctic Circle. In 1902 he undertook a tour in a British Napier accompanied by his wife and Charles Thomas. This more than unusual journey took him over 46,528 miles through 39 countries and he travelled countries which never before had seen an automobile. Prerequisite for this undertaking was meticulous preparation and he even travelled with special wheels to enable him to ride on railroad tracks. Always impeccably dressed, he was very aware of the publicity from which he took advantage of the automotive sector. So he corresponded with countless local and international newspapers, in this way he traveled to virtually all continents until 1908. In 1904 he took part in the first reliability race organized by the American Automobile Association, because he thought this should be a repeating event, he donated a silver trophy and a very large prize of 2000 U. S. dollars, which he repeated annually. The AAA Glidden organized this Glidden Reliability Tour regularly from 1905 to 1913, the aim was to go a certain distance within a certain time and omitting no checkpoint. The winner was decided by a points system, the first Glidden Tour was still perceived as too easy, the participants voted a winner. This was not, by the way, Charles Glidden with his Napier, in subsequent races, the course grew ever longer and more demanding
16.
London
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London /ˈlʌndən/ is the capital and most populous city of England and the United Kingdom. Standing on the River Thames in the south east of the island of Great Britain and it was founded by the Romans, who named it Londinium. Londons ancient core, the City of London, largely retains its 1. 12-square-mile medieval boundaries. London is a global city in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism. It is crowned as the worlds largest financial centre and has the fifth- or sixth-largest metropolitan area GDP in the world, London is a world cultural capital. It is the worlds most-visited city as measured by international arrivals and has the worlds largest city airport system measured by passenger traffic, London is the worlds leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. Londons universities form the largest concentration of education institutes in Europe. In 2012, London became the first city to have hosted the modern Summer Olympic Games three times, London has a diverse range of people and cultures, and more than 300 languages are spoken in the region. Its estimated mid-2015 municipal population was 8,673,713, the largest of any city in the European Union, Londons urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census. The citys metropolitan area is the most populous in the EU with 13,879,757 inhabitants, the city-region therefore has a similar land area and population to that of the New York metropolitan area. London was the worlds most populous city from around 1831 to 1925, Other famous landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Pauls Cathedral, Tower Bridge, Trafalgar Square, and The Shard. The London Underground is the oldest underground railway network in the world, the etymology of London is uncertain. It is an ancient name, found in sources from the 2nd century and it is recorded c.121 as Londinium, which points to Romano-British origin, and hand-written Roman tablets recovered in the city originating from AD 65/70-80 include the word Londinio. The earliest attempted explanation, now disregarded, is attributed to Geoffrey of Monmouth in Historia Regum Britanniae and this had it that the name originated from a supposed King Lud, who had allegedly taken over the city and named it Kaerlud. From 1898, it was accepted that the name was of Celtic origin and meant place belonging to a man called *Londinos. The ultimate difficulty lies in reconciling the Latin form Londinium with the modern Welsh Llundain, which should demand a form *lōndinion, from earlier *loundiniom. The possibility cannot be ruled out that the Welsh name was borrowed back in from English at a later date, and thus cannot be used as a basis from which to reconstruct the original name. Until 1889, the name London officially applied only to the City of London, two recent discoveries indicate probable very early settlements near the Thames in the London area
17.
Manchester
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Manchester is a major city and metropolitan borough in Greater Manchester, England, with a population of 514,414 as of 2013. It lies within the United Kingdoms second-most populous urban area, with a population of 2.55 million, Manchester is fringed by the Cheshire Plain to the south, the Pennines to the north and east and an arc of towns with which it forms a continuous conurbation. The local authority is Manchester City Council and it was historically a part of Lancashire, although areas of Cheshire south of the River Mersey were incorporated during the 20th century. Throughout the Middle Ages Manchester remained a township but began to expand at an astonishing rate around the turn of the 19th century. Manchesters unplanned urbanisation was brought on by a boom in textile manufacture during the Industrial Revolution, Manchester achieved city status in 1853. The Manchester Ship Canal opened in 1894, creating the Port of Manchester and its fortunes declined after the Second World War, owing to deindustrialisation. The city centre was devastated in a bombing in 1996, but it led to extensive investment, in 2014, the Globalization and World Cities Research Network ranked Manchester as a beta world city, the highest-ranked British city apart from London. Manchester is the third-most visited city in the UK and it is notable for its architecture, culture, musical exports, media links, scientific and engineering output, social impact, sports clubs and transport connections. Manchester Liverpool Road railway station was the worlds first inter-city passenger railway station and in the city scientists first split the atom, the name Manchester originates from the Latin name Mamucium or its variant Mancunium and the citizens are still referred to as Mancunians. These are generally thought to represent a Latinisation of an original Brittonic name, both meanings are preserved in languages derived from Common Brittonic, mam meaning breast in Irish and mother in Welsh. The suffix -chester is a survival of Old English ceaster and their territory extended across the fertile lowland of what is now Salford and Stretford. Central Manchester has been settled since this time. A stabilised fragment of foundations of the version of the Roman fort is visible in Castlefield. After the Roman withdrawal and Saxon conquest, the focus of settlement shifted to the confluence of the Irwell, much of the wider area was laid waste in the subsequent Harrying of the North. Thomas de la Warre, lord of the manor, founded and constructed a church for the parish in 1421. The church is now Manchester Cathedral, the premises of the college house Chethams School of Music. The library, which opened in 1653 and is open to the public today, is the oldest free public reference library in the United Kingdom. Manchester is mentioned as having a market in 1282, around the 14th century, Manchester received an influx of Flemish weavers, sometimes credited as the foundation of the regions textile industry
18.
International Bell Telephone Company
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IBTC rapidly evolved into an important European telephone service provider and manufacturer, with major operations in several countries. AT&T, its U. S. parent, later sold its entire European division and IBTCs subsidiaries to the International Telephone & Telegraph Company of Cuba in 1925, ending a 46-year presence on the Continent. During his tour of the continent the Belgian government offered him the greatest financial incentives to establish his European subsidiarys headquarters in their country, BTMC was created as a joint venture by the International Bell Telephone Company of New York and the Western Electric Company of Chicago. BTMC came under majority ownership by the telephone manufacturer Western Electric, Western Electric was itself later majority owned by the American Bell Telephone Company, returning control of BTMC back to the Bell organization. BTMC was owned 45% by American Bell Telephone, and 55% by Bells major U. S. supplier, Western Electric, a U. S. company formed during the era of the telegraph, became American Bells sole telephone supplier the same year. Barton had earlier sent him to Australia and New Zealand to help with operations there, Welles would lead the overseas BTMC company for the next 30 years assisted by Louis De Groof, a Belgian authorised agent. IBTC started up subsidiary manufacturing plants in cities throughout all of Europe. In the year after its founding BTMC employed 35 people, and its workshops were accommodated within a plant at No.4 Boudewijnstraat. The Antwerp facility was responsible for introducing the telephone to much of Europe, with its first manual. In 1884 the very first European intercity line was created between Antwerp and Brussels, and in 1887 the first international line in Europe was opened between Brussels and Paris, francis Welles retired from BTMC in 1913 and returned to the United States shortly before the First World War. Welles and was succeeded by Alexis Mois, the Great War inflicted severe damage to BTMCs operations and production facilities, much of which was destroyed or seized by the invading German army. The companys U. S. managers immediately departed for the United Kingdom or returned home, while many plant employees had been seconded to the Belgian army, or moved to other unoccupied countries. In its early existence the Bell Telephone Manufacturing Company of Belgium took on the role of a child of two often squabbling parents, Western Electric and the American Bell Telephone Company. However even through a succession of owners the BTMC has retained its original name, the first telephone exchanges in Belgium were opened in 1878. A company was formed in Brussels in 1879, and others followed, competition was recognised as unsatisfactory, and the various companies were encouraged to amalgamate. The Compagnie Belge du Téléphone Bell was formed in 1882, as the Belgian subsidiary of the International Bell Telephone Company of New York. By the end of 1886, the Belgian division had a total 6,900 kilometers of lines, and 3,532 subscribers in seven cities, including Brussels, Antwerp, Charleroi, Ghent, Verviers. The first exchange in Switzerland was opened in Zurich, operated under a license granted by the IBTC to a group of men on July 24,1880
19.
Antwerp
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Antwerp is a city in Belgium, the capital of Antwerp province in the region of Flanders. With a population of 510,610, it is the most populous city proper in Belgium and its metropolitan area houses around 1,200,000 people, which is second behind Brussels. Antwerp is on the River Scheldt, linked to the North Sea by the Westerschelde estuary, the Port of Antwerp is one of the biggest in the world, ranking second in Europe and within the top 20 globally. Antwerp has long been an important city in the Low Countries, the inhabitants of Antwerp are nicknamed Sinjoren, after the Spanish honorific señor or French seigneur, lord, referring to the Spanish noblemen who ruled the city in the 17th century. The city hosted the 1920 Summer Olympics, according to folklore, notably celebrated by a statue in front of the town hall, the city got its name from a legend about a giant called Antigoon who lived near the Scheldt river. He exacted a toll from passing boatmen, and for those who refused, he severed one of their hands, eventually the giant was killed by a young hero named Silvius Brabo, who cut off the giants own hand and flung it into the river. Hence the name Antwerpen, from Dutch hand werpen, akin to Old English hand and wearpan, a longstanding theory is that the name originated in the Gallo-Roman period and comes from the Latin antverpia. Antverpia would come from Ante Verpia, indicating land that forms by deposition in the curve of a river. Note that the river Scheldt, before a period between 600 and 750, followed a different track. This must have coincided roughly with the current ringway south of the city, however, many historians think it unlikely that there was a large settlement which would be named Antverpia, but more something like an outpost with a river crossing. However, John Lothrop Motley argues, and so do a lot of Dutch etymologists and historians, aan t werp is also possible. This warp is a hill or a river deposit, high enough to remain dry at high tide. Another word for werp is pol hence polders, historical Antwerp allegedly had its origins in a Gallo-Roman vicus. Excavations carried out in the oldest section near the Scheldt, 1952–1961, produced pottery shards, the earliest mention of Antwerp dates from the 4th century. In the 4th century, Antwerp was first named, having been settled by the Germanic Franks, the name was reputed to have been derived from anda and werpum. The Merovingian Antwerp was evangelized by Saint Amand in the 7th century, at the end of the 10th century, the Scheldt became the boundary of the Holy Roman Empire. Antwerp became a margraviate in 980, by the German emperor Otto I, in the 11th century Godfrey of Bouillon was for some years known as the marquis of Antwerp. In the 12th century, Norbert of Xanten established a community of his Premonstratensian canons at St. Michaels Abbey at Caloes
20.
Multiplexer
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In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n lines, which are used to select which input line to send to the output. Multiplexers are mainly used to increase the amount of data that can be sent over the network within a certain amount of time, a multiplexer is also called a data selector. Multiplexers can also be used to implement Boolean functions of multiple variables, conversely, a demultiplexer is a device taking a single input signal and selecting one of many data-output-lines, which is connected to the single input. A multiplexer is often used with a complementary demultiplexer on the receiving end, an electronic multiplexer can be considered as a multiple-input, single-output switch, and a demultiplexer as a single-input, multiple-output switch. The schematic symbol for a multiplexer is a trapezoid with the longer parallel side containing the input pins. The schematic on the shows a 2-to-1 multiplexer on the left. The s e l wire connects the desired input to the output, one use for multiplexers is economizing connections over a single channel, by connecting the multiplexers single output to the demultiplexers single input. The image to the right demonstrates this benefit, in this case, the cost of implementing separate channels for each data source is higher than the cost and inconvenience of providing the multiplexing/demultiplexing functions. At the receiving end of the data link a complementary demultiplexer is usually required to break the data stream back down into the original streams. In some cases, the far end system may have functionality greater than a simple demultiplexer, often, a multiplexer and demultiplexer are combined together into a single piece of equipment, which is conveniently referred to as a multiplexer. Both circuit elements are needed at both ends of a transmission link because most communications systems transmit in both directions, in analog circuit design, a multiplexer is a special type of analog switch that connects one signal selected from several inputs to a single output. In digital circuit design, the wires are of digital value. In the case of a 2-to-1 multiplexer, a value of 0 would connect I0 to the output while a logic value of 1 would connect I1 to the output. In larger multiplexers, the number of pins is equal to ⌈ log 2 ⌉ where n is the number of inputs. For example,9 to 16 inputs would require no fewer than 4 selector pins and 17 to 32 inputs would require no fewer than 5 selector pins, the binary value expressed on these selector pins determines the selected input pin. A straightforward realization of this 2-to-1 multiplexer would need 2 AND gates, an OR gate, while this is mathematically correct, it should be noted that a direct physical implementation would be prone to race conditions that require additional gates to suppress. Larger multiplexers are also common and, as stated above, require ⌈ log 2 ⌉ selector pins for n inputs, other common sizes are 4-to-1, 8-to-1, and 16-to-1
21.
Telephone switchboard
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The switchboard was an essential component of a manual telephone exchange, and was operated by switchboard operators who used electrical cords or switches to establish the connections. The electromechanical automatic telephone exchange, invented by Almon Strowger in 1888, in 1919, the Bell System in the United States also adopted automatic switching as its future technology, after years of reliance on manual systems. Nevertheless, many manual branch exchanges remained operational into the half of the 20th century in many enterprises. Later electronic devices and computer technology gave the access to an abundance of features. A private branch exchange in a business usually has an attendant console for the operator, or an auto-attendant, following the invention of the telephone in 1876, the first telephones were rented in pairs which were limited to conversation between the parties operating those two instruments. The use of an exchange was soon found to be even more advantageous than in telegraphy. In January 1878 the Boston Telephone Dispatch company had started hiring boys as telephone operators, thus, on September 1,1878, Boston Telephone Dispatch hired Emma Nutt as the first woman operator. Small towns typically had the switchboard installed in the home so that he or she could answer calls on a 24-hour basis. In 1894, New England Telephone and Telegraph Company installed the first battery-operated switchboard on January 9 in Lexington, Early switchboards in large cities usually were mounted floor to ceiling in order to allow the operators to reach all the lines in the exchange. The operators were boys who would use a ladder to connect to the higher jacks, late in the 1890s this measure failed to keep up with the increasing number of lines, and Milo G. Kellogg devised the Divided Multiple Switchboard for operators to work together, with a team on the A board and these operators were almost always women until the early 1970s, when men were once again hired. Cord switchboards were often referred to as cordboards by telephone company personnel, conversion to Panel switch and other automated switching systems first eliminated the B operator and then, usually years later, the A. Rural and suburban switchboards for the most part remained small and simple, in many cases, customers came to know their operator by name. As telephone exchanges converted to service, switchboards continued to serve specialized purposes. Before the advent of direct-dialed long distance calls, a subscriber would need to contact the operator in order to place a toll call. In large cities, there was often a number, such as 112. Elsewhere, the subscriber would ask the operator to ring the long-distance operator. The long distance operator would record the name and city of the person to be called, each toll center had only a limited number of trunks to distant cities, and if those circuits were busy, the operator would try alternate routings through intermediate cities
22.
Phone connector (audio)
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A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a common family of electrical connector typically used for analog signals, primarily audio. It is cylindrical in shape, typically two, three, four and, recently, five contacts. Three-contact versions are known as TRS connectors, where T stands for tip, R stands for ring, similarly, two-, four- and five- contact versions are called TS, TRRS and TRRRS connectors respectively. The phone connector was invented for use in telephone switchboards in the 19th century and is widely used. In its original configuration, the diameter of the sleeve conductor is 1⁄4 inch. The mini connector has a diameter of 3.5 mm, specific models are termed stereo plug, mini-stereo, mini jack, headphone jack and microphone jack, or are referred to by size, i. e.3. 5mm or 6. 35mm. In the UK, the terms jack plug and jack socket are commonly used for the male and female phone connectors. In the US, an electrical connector is called a jack. Phone plugs and jacks are not to be confused with the similar terms phono plug and phono jack which refer to RCA connectors common in consumer hi-fi, the 3.5 mm connector is, however, sometimes—but counter to the connector manufacturers nomenclature—referred to as mini phono. Modern phone connectors are available in three standard sizes, the original 1⁄4 in version dates from 1878, when it was used for manual telephone exchanges, making it the oldest electrical connector standard still in use. The 3.5 mm or miniature and 2.5 mm or sub-miniature sizes were originally designed as two-conductor connectors for earpieces on transistor radios since the 1950s, the standard still used today. The 3.5 mm connector, which is the most commonly used in application today, was popularized by the Sony EFM-117J radio which was released in 1964. It became very popular with its application on the Walkman in 1979, the 3.5 mm and 2.5 mm sizes are sometimes referred to as 1⁄8 in and 3⁄32 in respectively in the United States, though those dimensions are only approximations. All three sizes are now available in two-conductor and three-conductor versions. Four- and five-conductor versions of the 3.5 mm plug are used for certain applications, a four-conductor version is often used in compact camcorders and portable media players, and sometimes also in laptop computers and smartphones, providing stereo sound plus a video signal. Proprietary interfaces using both four- and five-conductor versions exist, where the conductors are used to supply power for accessories. The four-conductor 3.5 mm plug is used as a connector on handheld amateur radio transceivers from Yaesu. It is also used in some amps like the LH Labs Geek Out V2+ for a balanced output, the most common arrangement remains to have the male plug on the cable and the female socket mounted in a piece of equipment, the original intention of the design
23.
Telephone line
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A telephone line or telephone circuit is a single-user circuit on a telephone communication system. Telephone lines are used to deliver landline telephone service and Digital subscriber line phone service to the premises. Telephone overhead lines are connected to the switched telephone network. Modern lines may run underground, and may carry analog or digital signals to the exchange, often the customer end of that wire pair is connected to a data access arrangement, the telephone company end of that wire pair is connected to a telephone hybrid. In most cases, two wires for each telephone line run from a home or other small building to a local telephone exchange. The wires between the box and the exchange are known as the local loop, and the network of wires going to an exchange. The vast majority of houses in the U. S. are wired with 6-position modular jacks with four conductors wired to the junction box with copper wires. Those wires may be connected back to two telephone lines at the local telephone exchange, thus making those jacks RJ14 jacks. More often, only two of the wires are connected to the exchange as one line, and the others are unconnected. In that case, the jacks in the house are RJ11, inside the walls of the house—between the houses outside junction box and the interior wall jacks—the most common telephone cable in new houses is Category 5 cable—4 pairs of 24 AWG solid copper. Inside large buildings, and in the cables that run to the telephone company POP
24.
Trunking
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In telecommunications, trunking is a method for a system to provide network access to many clients by sharing a set of lines or frequencies instead of providing them individually. This is analogous to the structure of a tree with one trunk, examples of this include telephone systems and the two-way radios commonly used by police agencies. More recently port trunking has been applied in computer networking as well, a trunk is a single transmission channel between two points, each point being either the switching center or the node. In two-way radio communications, trunking refers to the ability of transmissions to be served by free channels whose availability is determined by algorithmic protocols, the cashier represents each radio channel, and each customer represents a radio user transmitting on their radio. Trunked radio systems pool all of the cashiers into one group, in a TRS, individual transmissions in any conversation may take place on several different channels. In the shopping analogy, this is as if a family of shoppers checks out all at once and are assigned different cashiers by the traffic manager, similarly, if a single shopper checks out more than once, they may be assigned a different cashier each time. Trunked radio systems provide greater efficiency at the cost of greater management overhead, the store managers orders must be conveyed to all the shoppers. This is done by assigning one or more channels as the control channel. TRSs have grown massively in their complexity since their introduction, and this is similar to the idea of a chain of grocery stores. The shopper generally goes to the nearest grocery store, but if there are complications or congestion, TRSs have greater risks to overcome than conventional radio systems in that a loss of the store manager would cause the systems traffic to no longer be managed. In this case, most of the time the TRS will automatically switch to a control channel, or in more rare circumstances. In spite of these risks, TRSs usually maintain reasonable uptime, trunk lines are used for connecting a private branch exchange to a telephone service provider. When needed they can be used by any telephone connected to the PBX, Trunking saves cost, because there are usually fewer trunk lines than extension lines, since it is unusual in most offices to have all extension lines in use for external calls at once. Trunk lines transmit voice and data in such as analog, T1, E1. The dial tone lines for outgoing calls are called DDCO trunks, in the UK and the Commonwealth countries, a trunk call was the term for long distance calling, involving more than one telephone exchange, in contrast to making a local call. Trunking also refers to the connection of switches and circuits within a telephone exchange, Trunking is closely related to the concept of grading. Trunking allows a group of switches at the same time. Thus the service provider can provide a number of circuits than might otherwise be required, allowing many users to share a smaller number of connections
25.
Ringdown
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In telephony, ringdown is a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp or cause the operation of a self-locking relay known as a drop. Ringdown is used in operation, as distinguished from automatic signaling by dialing a number. The signal consists of a continuous or pulsed alternating current signal transmitted over the line and it may be used with or without a telephone switchboard. The last ringdown telephone exchange in the United States was located at Bryant Pond, Maine, had 400+ subscribers, on some systems, this function was carried out by the inward operator. In an application not involving a telephone operator, a two-point automatic ringdown circuit, when the telephone at one end goes off-hook, the phone at the other end instantly rings. No dialing is involved and therefore telephone sets without dials are sometimes used, many ringdown circuits work in both directions. In some cases a circuit is designed to work in one direction only and that is, going off-hook at one end rings the other. Going off-hook at end B has no effect at end A. Ringdown features are part of a key telephone system. In the wire spring relay key service units of the Bell System 1A2, in the 400-series units, a number of different KTUs operate a ringdown, including the model 415. In other situations, the ringdown is powered and operated by equipment inside the telephone exchange, in the case of enterprises with a private branch exchange switch, the ringdown can be operated by the PBX key. The switch is programmed to ring a specific extension when a defined extension goes off-hook, the PBX does not offer dial tone to the calling extension, it only detects on-hook or off-hook status. These circuits are used, over high-volume routes where one site calls another very frequently, Example, an information desk and the information desk staff supervisors desk. Where a tamper-proof ability to call from one point to another is needed, Example, a phone used to summon a taxicab to an airport or hotel. Where a limited ability to contact one entity is desired, Example, a house phone in a hotel lobby to the live operator at the hotels switchboard where the public, or users that are not trained in using a specific office telephone system, must place calls. Example, the phone to reach the watchman from the front door at a warehouse. In locations where emergencies are handled and the required to dial digits would cause an unacceptable delay in handling of an emergency. Example, a control tower to the airports fire station or fire dispatch center. Example, Independent System Operator communication to a power plant, in situations where the called party needs to be certain of who is calling
26.
Almon Brown Strowger
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Almon Brown Strowger was an American inventor who gave his name to the Strowger switch, an electromechanical telephone exchange technology that his invention and patent inspired. Strowger was born in Penfield, New York, near Rochester, little information is available about his early life, but it is known that he was the grandson of the second settler and first miller in Penfield. He taught school in Penfield for a time, and served in the 8th New York Volunteer Cavalry during the American Civil War and it is believed that he fought in the Second Battle of Bull Run near Manassas, Virginia. After the Civil War, it appears he first became a school teacher before he became an undertaker. He is variously attributed as living in El Dorado, Kansas, or Topeka, Kansas, and finally Kansas City, Missouri. It is not clear where his idea of a telephone exchange was originally conceived. Anecdotally, Strowgers undertaking business was losing clients to a competitor whose telephone-operator wife was redirecting everyone who called for Strowger, motivated to remove the intermediary operator, he invented the first automatic telephone exchange in 1889 and received its patent in 1891. It is reported that he constructed a model of his invention from a round collar box. He married Susan A. from Massachusetts in 1897 as his second wife, Strowger sold his patents to his associates in 1896 for $1,800 and sold his share in the Automatic Electric Company for $10,000 in 1898. His patents subsequently sold to Bell Systems for $2.5 million in 1916, the companys engineers continued development of Strowgers designs and submitted several patents in the names of its employees. It also underwent several name changes, Strowger himself seems to have not taken part in this further development. He subsequently moved to St. Petersburg, Florida and appears to have returned to being an undertaker, bussey Funeral Home records report an unidentified body being moved for Mr. Strowger in December 1899. The same funeral home subsequently buried Strowger himself, Strowger was a man of some wealth at his death and was reported as owning at least a city block of property. He died, aged 62, of an aneurysm after suffering from anemia, at St. Petersburg, Pinellas County and his grave is marked with the traditional white headstone with an inscription that reads, Lieut. He was survived by his widow Susan A. Strowger and she had claimed that her husband had only received $10,000 for his invention, when he should have received $1,000,000. A bronze plaque, to commemorate his invention, was placed on his grave in 1945 by telephone company officials, Strowger was admitted to the hall of fame of the U. S. Apart from his invention, his name has also given to a locomotive. In 2003, the Verizon Foundation awarded $4500 to Pinellas Heritage, Inc. the funds were used to develop a website to impart the history of the cemetery where Strowger is buried, and to restore two Civil War memorials
27.
Kansas City, Missouri
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Kansas City is the largest city in Missouri and the sixth largest city in the Midwest. According to the U. S. Census Bureau, the city had an population of 475,378 in 2015. It is the city of the Kansas City metropolitan area. Kansas City was founded in the 1830s as a Missouri River port at its confluence with the Kansas River coming in from the west, on June 1,1850 the town of Kansas was incorporated, shortly after came the establishment of the Kansas Territory. Confusion between the two ensued and the name Kansas City was assigned to them soon thereafter. Most of the city lies within Jackson County, but portions spill into Clay, Cass, along with Independence, it serves as one of the two county seats for Jackson County. Major suburbs include the Missouri cities of Independence and Lees Summit and the Kansas cities of Overland Park, Olathe, and Kansas City. The city is composed of neighborhoods, including the River Market District in the north, the 18th and Vine District in the east. Kansas City is also known for its cuisine, its craft breweries, Kansas City, Missouri was officially incorporated as a town on June 1,1850, and as a city on March 28,1853. The territory straddling the border between Missouri and Kansas at the confluence of the Kansas and Missouri rivers was considered a place to build settlements. The Antioch Christian Church, Dr. James Compton House, the first documented European visitor to Kansas City was Étienne de Veniard, Sieur de Bourgmont, who was also the first European to explore the lower Missouri River. Criticized for his response to the Native American attack on Fort Détroit, Bourgmont lived with a Native American wife in a village about 90 miles east near Brunswick, Missouri, where he illegally traded furs. In the documents, he describes the junction of the Grande Riv des Cansez and Missouri River, French cartographer Guillaume Delisle used the descriptions to make the areas first reasonably accurate map. The Spanish took over the region in the Treaty of Paris in 1763, the French continued their fur trade under Spanish license. After the 1804 Louisiana Purchase, Lewis and Clark visited the confluence of the Kansas and Missouri rivers, in 1831, a group of Mormons from New York settled in what would become the city. They built the first school within Kansas Citys current boundaries, but were forced out by mob violence in 1833, in 1833 John McCoy established West Port along the Santa Fe Trail,3 miles away from the river. In 1834 McCoy established Westport Landing on a bend in the Missouri to serve as a point for West Port. Soon after, the Kansas Town Company, a group of investors, began to settle the area, in 1850, the landing area was incorporated as the Town of Kansas
28.
Stepping switch
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The major use of stepping switches was in early automatic telephone exchanges to route telephone calls. Later, they were used in such equipment as industrial control systems. They were used in Japanese cypher machines during World War 2, known to the Americans as CORAL, JADE, code breakers at Bletchley Park employed uniselectors driven by a continuously rotating motor rather than a series of pulses in the Bombe machines to cryptanalyse the German Enigma ciphers. In a uniselector, the stepping switch steps only on one axis, in other types, such as the Strowger switch, mechanical switching occurs on two directions, across a grid of contacts. The Strowger switch was invented by Almon Brown Strowger in 1888, stepping switches were widely used in telephony and industrial control systems when electromechanical technology was paramount. A basic stepping switch is an electrically operated rotary switch with a single terminal, like other typical rotary switches, the single terminal connects to one of the multiple terminals by rotating a contact arm, sometimes called a wiper, to the desired position. Moving from one position to the next is called stepping, hence the name of the mechanism, using traditional terminology, this is a single-pole, multi-position switch. While some stepping switches have one pole, a typical switch has more, in the latter case, all wipers are aligned. Hence, one input with multiple wires could be connected to one of multiple outputs, in this configuration, the rotating contacts resembled the head support arms in a modern hard disk drive. Multipole switches were common, some had perhaps as many as a dozen poles, most switches have a bank of stationary contacts extending over half a cylinder, while some have only a third of a cylinder. The typical half-cylinder switch has two sets of wiper contacts opposite each other, while the third of a cylinder type has three sets, equally spaced. For any given level, both or all three wipers are connected, so it makes no difference which of the two is connecting, an electromagnet advances the wipers to the next position when fed with a pulse of DC. The magnets armature operates a pawl that advances a ratchet, when the pawl reaches its full stroke, it blocks the ratchet so it and the wipers will not overshoot. When power to the coil disconnects, the spring retracts the pawl, another pawl pivoted on the frame ensures that the wipers do not move backward, contact friction keeps them in place. Some uniselector designs step on application of the pulse, others step on its removal. In most applications, such as telephony, it is desirable to be able to return the wipers to a home position, some switches have a cam attached to the wiper shaft. This cam operates a set of contacts when the wiper is at home position, other circuit designs used one level of the contacts to home the wipers, so the separate homing contacts were not needed. Typical stepping switches have contacts directly operated by the stepping magnets armature, the external control circuits remove power when the wipers reach the desired position, that could be the home position
29.
Rotary dial
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A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing. It is used when initiating a call to transmit the destination telephone number to a telephone exchange. When released at the stop, the wheel returns to its home position by spring action at a speed regulated by a governor device. Each of the ten digits are encoded in sequences of up to ten pulses, for this reason, the method is sometimes called decadic dialling. The first patent for a dial is due to Almon Brown Strowger as U. S. Patent 486,909, but the known form with holes in the finger wheel was not introduced until ca. Touch-tone technology primarily used a keypad in form of an array of push-buttons for dialing. From as early as 1836 onward, various suggestions and inventions of dials for sending telegraph signals were reported, after the first commercial telephone exchange was installed in 1878, the need for an automated, user-controlled method of directing a telephone call became apparent. Addressing the technical shortcomings, Almon Brown Strowger invented a dial in 1891. Most inventions involved costly, intricate mechanisms and required the user to perform complex manipulations, the original dials required complex operational sequences. A workable, albeit error-prone, system was invented by the Automatic Electric Company using three push-buttons on the telephone and these buttons represented the hundreds, tens, and single units of a telephone number. When calling the subscriber number 163, for example, the user had to push the button once, followed by six presses of the tens button. In 1896, this system was supplanted by an automatic contact-making machine, further development continued during the 1890s and the early 1900s in conjunction with improvements in switching technology. Almon Brown Strowger was the first to file a patent for a dial on December 21,1891. In the 1950s, plastic materials were introduced in dial construction, replacing metal which was heavier, despite their lack of modern features, rotary phones occasionally find special uses. They are also retained for authenticity in historic properties such as the U. S. Route 66 Blue Swallow Motel which date from an era of named exchanges, a rotary dial typically features a circular construction. The shaft that actuates the mechanical switching mechanism is driven by the finger wheel, the finger wheel may be transparent or opaque permitting the viewing of the face plate, or number plate below, either in whole, or only showing the number assignment for each finger hole. The faceplate is printed with numbers, and sometimes letters, corresponding to each finger hole, a curved device called a finger stop sits above the dial at approximately the 4 oclock position
30.
Panel switch
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The Panel Machine Switching System is an early type of automatic telephone exchange for urban service, introduced in the Bell System in the 1920s. Both systems had many features in common, the first Panel-type exchanges were placed in service in Newark, New Jersey, on January 16,1915 at the Mulberry central office, and on June 12 in the Waverly central office. These system were semi-mechanical systems using telephones at customer stations without a dial, operators answered calls and keyed the station number into the panel switch. Most Panel installations were replaced by modern systems during the 1970s, the Panel switch was named for its tall panels covered with 500 rows of terminals. Each panel had a motor to drive usually sixty selectors by electromagnetically controlled clutches. The selector was similar in effect to a stepping switch though it moved continuously over the contacts, each selector had five brushes, each of which could select from 100 terminals arranged in groups. As in the Strowger system, each office could address up to 10,000 numbered lines. The panel system was designed to interconnect the offices of a city or a calling area. Each office was assigned a two- digit office code, callers dialed the office code followed by the station number. In most situations this led to six-digit numbers, but from the beginning the panel system handled seven-digit numbers, for two reasons. Party line numbers were listed with one of the letters J, M, R, the caller dialed the office code, the line number, and the digit corresponding to the letter. The panel system was designed to work with manual offices of up to 10,500 lines, to call a line in a manual office, callers dialed the office code followed by the line number, just as they would when calling a number in a fully automatic office. For lines 10,000 and up, callers dialed the office code. A subscribers line had two appearances in an office, one on the originating side, and one on the terminating side. The cutoff relay was controlled by a lead that, as with the multiple switchboard. The final selector performed a sleeve test to detect a busy line when a subscriber was called, supervision was supplied by a District circuit, similar to the plug and light cord circuit that plugged into a line jack on a switchboard. Some District frames were equipped with the more complex supervisory and timing circuits required to generate coin collect, many of the urban and commercial areas where Panel was first used had message rate service rather than flat rate calling. The introduction of direct distance dialing in the 1950s required the addition of automatic number identification equipment for centralized automatic message accounting
31.
Crossbar switch
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In electronics, a crossbar switch is a collection of switches arranged in a matrix configuration. Originally, a crossbar switch consisted literally of crossing metal bars that provided the input and output paths, later implementations achieved the same switching topology in solid state semiconductor chips. The cross-point switch is one of the principal switch architectures, together with a switch, memory switch. A crossbar switch is an assembly of individual switches between a set of inputs and a set of outputs, the switches are arranged in a matrix. If the crossbar switch has M inputs and N outputs, then a crossbar has a matrix with M × N cross-points or places where the connections cross, at each crosspoint is a switch, when closed, it connects one of the inputs to one of the outputs. A given crossbar is a layer, non-blocking switch. Non-blocking means that other concurrent connections do not prevent connecting other inputs to other outputs, collections of crossbars can be used to implement multiple layer and blocking switches. A crossbar switching system is called a coordinate switching system. Crossbar switches are used in information processing applications such as telephony and circuit switching. The matrix layout of a switch is also used in some semiconductor memory devices. Here the bars are thin metal wires, and the switches are fusible links. The fuses are blown or opened using high voltage and read using low voltage, such devices are called programmable read-only memory. At the 2008 NSTI Nanotechnology Conference a paper was presented which discussed a nanoscale crossbar implementation of an adding circuit used as an alternative to logic gates for computation, matrix arrays are fundamental to modern flat-panel displays. Thin-film-transistor LCDs have a transistor at each crosspoint, so they could be considered to include a switch as part of their structure. In a typical installation, all the sources are located on an equipment rack. Where central control of the matrix is practical, a typical rack-mount matrix switch offers front-panel buttons to allow connection of inputs to outputs. An example of such a usage might be a sports bar, ordinarily, a sports bar would install a separate desk top box for each display for which independent control is desired. Such switches are used in home theater applications
32.
Dual-tone multi-frequency signaling
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DTMF was first developed in the Bell System in the United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardized by ITU-T Recommendation Q.23 and it is also known in the UK as MF4. The Touch-Tone system using a telephone keypad gradually replaced the use of dial and has become the industry standard for landline. Other multi-frequency systems are used for internal signaling within the telephone network, prior to the development of DTMF, telephone numbers were dialed by users with a loop-disconnect signaling, more commonly known as pulse dialing in the U. S. The exchange equipment responds to the dial pulses either directly by operating relays, the physical distance for which this type of dialing was possible was restricted by electrical distortions and was only possible on direct metallic links between end points of a line. Placing calls over longer distances required either operator assistance or provision of special subscriber trunk dialing equipment, operators used an earlier type of multi-frequency signaling. Multi-frequency signaling is a group of signaling methods that use a mixture of two pure tone sounds, various MF signaling protocols were devised by the Bell System and CCITT. This semi-automated signaling and switching proved successful in both speed and cost effectiveness, the DTMF system uses a set of eight audio frequencies transmitted in pairs to represent 16 signals, represented by the ten digits, the letters A to D, and the symbols # and *. AT&T described the product as a method for pushbutton signaling from customer stations using the transmission path. DTMF was known throughout the Bell System by the trademark Touch-Tone, the term was first used by AT&T in commerce on July 5,1960 and was introduced to the public on November 18,1963, when the first push-button telephone was made available to the public. It was a trademark by AT&T from September 4,1962 to March 13,1984. It is standardized by ITU-T Recommendation Q.23, in the UK, it is also known as MF4. Other vendors of compatible telephone equipment called the Touch-Tone feature tone dialing or DTMF, previously, terrestrial television stations used DTMF tones to control remote transmitters. The engineers had envisioned telephones being used to access computers, and they consulted with companies to determine the requirements. This led to the addition of the sign and asterisk or star keys as well as a group of keys for menu selection. Public payphones that accept credit cards use these codes to send the information from the magnetic strip. The AUTOVON telephone system of the United States Armed Forces used these signals to assert certain privilege, precedence is still a feature of military telephone networks, but using number combinations. For example, entering 93 before a number is a priority call, present-day uses of the A, B, C and D signals on telephone networks are few, and are exclusive to network control
33.
Telephone exchange
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A telephone exchange is a telecommunications system used in the public switched telephone network or in large enterprises. In historical perspective, telecommunication terms have been used with different semantics over time, the term telephone exchange is often used synonymously with central office, a Bell System term. Often, an office is defined as a building used to house the inside plant equipment of potentially several telephone exchanges. Such an area has also referred to as the exchange. Central office locations may also be identified in North America as wire centers, All central offices within a larger region, typically aggregated by state, were assigned a common numbering plan area code. For corporate or enterprise use, a telephone exchange is often referred to as a private branch exchange. Smaller installations might deploy a PBX or key telephone system in the office of a receptionist and this made it possible for subscribers to call each other at homes, businesses, or public spaces. These made telephony an available and comfortable communication tool for everyday use, one of the first to propose a telephone exchange was Hungarian Tivadar Puskás in 1877 while he was working for Thomas Edison. The first experimental telephone exchange was based on the ideas of Puskás, the worlds first commercial telephone exchange opened on November 12,1877 in Friedrichsberg close to Berlin. George W. Coy designed and built the first commercial US telephone exchange opened in New Haven. The switchboard was built from carriage bolts, handles from teapot lids and bustle wire, Charles Glidden is also credited with establishing an exchange in Lowell, MA. with 50 subscribers in 1878. In Europe other early telephone exchanges were based in London and Manchester, Belgium had its first International Bell exchange a year later. In 1887 Puskás introduced the multiplex switchboard, later exchanges consisted of one to several hundred plug boards staffed by switchboard operators. Each operator sat in front of a panel containing banks of ¼-inch tip-ring-sleeve jacks. In front of the jack panel lay a horizontal panel containing two rows of patch cords, each connected to a cord circuit. When a calling party lifted the receiver, the loop current lit a signal lamp near the jack. The operator responded by inserting the rear cord into the jack and switched her headset into the circuit to ask, Number. For a local call, the operator inserted the front cord of the pair into the partys local jack
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