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Director Telephone System
The director telephone system was a development of the Strowger or step-by-step (SXS) switching system used in London and five other large cities in the UK from the 1920s to the 1980s. A large proportion (c. 70% to 80%) of telephone traffic in large metropolitan areas is outgoing traffic, and it is distributed over many exchanges. A non-director SXS exchange system is not suitable for these areas. As the translation facility incorporated was similar to the register in common control systems, the director system incorporates two features of the Panel system, which was introduced in large American cities, and which were required regardless of the type of exchange system for these large areas, which would have a mixture of manual and automatic exchanges for some years. Customer stations were assigned seven-digit numbers, with the first three digits spelling out the local exchange name; this expedited call handling particularly to and from manual exchanges. Direct or tandem junctio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strowger Switch
The Strowger switch is the first commercially successful electromechanical stepping switch telephone exchange system. It was developed by the Strowger Automatic Telephone Exchange Company founded in 1891 by Almon Brown Strowger. Because of its operational characteristics, it is also known as a step-by-step (SXS) switch. History Strowger, an undertaker, was motivated to invent an automatic telephone exchange after having difficulties with his telephone service. He became convinced that the manual telephone exchange operators were deliberately interfering with his calls, leading to loss of business. According to the local Bell Telephone Company manager Herman Ritterhoff, Strowger swore to "get even" with the telephone operators and "put every last one of them out of a job." Ritterhoff claimed that the real cause of Strowger's difficulties was a metal sign hung on his wall over his telephone, causing an intermittent short circuit when blown by the wind. Strowger conceived ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Exchanges
telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers. 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, a ''central office'' is defined as a building used to house the inside plant equipment of potentially several telephone exchanges, each serving a certain geographical area. Such an area has also been referred to as the exchange or exchange area. In North America, a central office location may also be identified as a ''wire center'', designating a facility to which a telephone is connected and obtains dial tone. For business and billing purposes, telecommunication carriers defin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephony In Greater Manchester
The Cities of Manchester and Salford and some surrounding urban areas such as Stockport, Oldham and Bolton, (now forming parts of Greater Manchester), were the location of several advances in the development of telephony in the United Kingdom. A Manchester company installed the country's first regular telephone system in the city, wiring solutions which were adopted across Britain were initiated in Manchester and Stockport, the city was (arguably) the site of the UK's first telephone exchange and a service which was the forerunner of modern mobile phones was controlled from the city. UK’s first regular telephone service In November 1877, while telephony was in its infancy, just 18 months after Alexander Graham Bell had made the world's first phone call, Charles Moseley, the son of a Manchester rubber manufacturer (then making telegraph equipment), took an interest in Bell's work. Moseley employed an engineer called William Fereday Bottomley to obtain telephone instruments fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Telephone Exchanges In London
This is a list of telephone exchanges located within Greater London. Occasionally, in areas of high demand, two exchanges are located at the same premises; for example Canary Wharf and Poplar. History London had a large network of manual exchanges (80 in 1927) and individual telephone exchanges were given names, e.g. Ebbsfleet; a caller asked the operator for Ebbsfleet 1234. However, although the General Post Office (GPO) had commenced installation of automatic exchanges from 1912, the basic Strowger or SXS switch adopted as standard by the GPO was not suitable for large cities like London. So from 1927 a development of the SXS switch was installed in London, the Director system; first at HOLborn followed by BIShopgate and SLOane exchanges and then WEStern and MONument. Telephones on automatic exchanges had letters as well as numbers marked on the telephone dial, and calls to London numbers used the first three letters of the exchange name followed by four digits, e.g. EUS 123 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sender
A sender was a special type of circuit in 20th-century electromechanical telephone exchanges which registered the telephone numbers dialed by the subscriber, and then transmitted that information to another exchange. In some American exchange designs, for example, the No. 1 Crossbar switch there were both originating senders and terminating senders. The corresponding device in the British director telephone system was called a "director" and, in other contexts, "register". History The sender concept was developed to meet the needs of large city telephone switching systems, where the total number of subscriber lines and multiple central offices throughout the city required complex switching arrangements that were not easily handled by the direct control systems then in use, such as the step by step, or Strowger system. These limitations included inefficient trunking in large service areas, and a limited ability for growth and reorganization as additional subscribers were added. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Independent Telephone Company
An independent telephone company was a telephone company providing local service in the United States or Canada that was not part of the Bell System organized by American Telephone and Telegraph. Independent telephone companies usually operated in many rural or sparsely populated areas. United States The second fundamental Bell patent for telephones expired on 30 January 1894, which provided an opportunity for independent companies to provide telephone services, although some had been established before that date. The Strowger Automatic Telephone Exchange company had been formed on 30 October 1891. The first Strowger switch went into operation on 3 November 1892 in LaPorte, Indiana, with 75 subscribers and capacity for 99. Independent manufacturing companies were established, such as Stromberg-Carlson in 1894 and Kellogg Switchboard & Supply Company in 1897. By 1903 while the Bell system had 1,278,000 subscribers on 1,514 main exchanges, the independents, excluding non-profit r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world's most populous megacities. Los Angeles is the commercial, financial, and cultural center of Southern California. With a population of roughly 3.9 million residents within the city limits , Los Angeles is known for its Mediterranean climate, ethnic and cultural diversity, being the home of the Hollywood film industry, and its sprawling metropolitan area. The city of Los Angeles lies in a basin in Southern California adjacent to the Pacific Ocean in the west and extending through the Santa Monica Mountains and north into the San Fernando Valley, with the city bordering the San Gabriel Valley to it's east. It covers about , and is the county seat of Los Angeles County, which is the most populous county in the United States with an estim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Number One Crossbar Switching System
The Number One Crossbar Switching System (1XB), was the primary technology for urban telephone exchanges served by the Bell System in the mid-20th century. Its switch fabric used the electromechanical crossbar switch to implement the topology of the panel switching system of the 1920s. The first No. 1 Crossbar was installed in the PResident-2 central office at Troy Avenue in Brooklyn, New York which became operational in February 1938. Evolution The predecessor to the No. 1 Crossbar was the panel system, which was used in many large metropolitan areas beginning in the early 1920s. By the 1930s, there was a growing need for a new type of switching machine that did not have the drawbacks inherent in the panel system. Desirable features of the crossbar system included: * Elimination of the motor-driven equipment * Reduction in the number of unique parts * Reduction in the cost of maintenance * Bifurcated, precious metal relay contacts, resulting in improved contact performance a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panel Switch
The Panel Machine Switching System is a type of automatic telephone exchange for urban service that was used in the Bell System in the United States for seven decades. The first semi-mechanical types of this design were installed in 1915 in Newark, New Jersey, and the last were retired in the same city in 1983. The Panel switch was named for its tall panels which consisted of layered strips of terminals. Between each strip was placed an insulating layer, which kept each metal strip electrically isolated from the ones above and below. These terminals were arranged in ''banks'', five of which occupied an average selector frame. Each bank contained 100 sets of terminals, for a total of 500 sets of terminals per frame. At the bottom, the frame had two electric motors to drive sixty selectors up and down by electromagnetically controlled clutches. As calls were completed through the system, selectors moved vertically over the sets of terminals until they reached the desired location, at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell System
The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America for over one hundred years from its creation in 1877 until its antitrust breakup in 1983. The system of companies was often colloquially called Ma Bell (as in "Mother Bell"), as it held a vertical monopoly over telecommunication products and services in most areas of the United States and Canada. At the time of the breakup of the Bell System in the early 1980s, it had assets of $150 billion (equivalent to $ billion in ) and employed over one million people. Ever since the 1910s, American antitrust regulators had been observing and accusing the Bell System of abusing its monopoly power, and had brought legal action multiple times over the decades, until in 1974 the Antitrust Division of the U.S. Department of Justice brought a lawsuit against Be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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