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Tandem Switch
A class-4, or tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the public switched telephone network. A class-4 switch does not connect directly to telephones; instead, it connects to other class-4 switches and to class-5 telephone switches. The telephones of service subscribers are wired to class-5 switches. When a call is placed to a telephone that is not on the same class-5 switch as the originating subscriber, the call may be routed through one or more class-4 switches to reach its destination. Etymology ''Tandem'' derives from the Latin adverb ''tandem'' meaning ''at length'', and is used in English to mean a group of two people or machines working together, usually in series. A tandem switch is used to interconnect other switches via trunks. Thus, tandem switches are always part of a series of switches and lines that connect telephone callers to e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone Company
A telecommunications company is a kind of electronic communications service provider, more precisely a telecommunications service provider (TSP), that provides telecommunications services such as telephony and data communications access. Many traditional solely telephone companies now function as internet service providers (ISPs), and the distinction between a telephone company and ISP has tended to disappear completely over time, as the current trend for supplier convergence in the industry develops. Additionally, with advances in technology development, other traditional separate industries such as cable television, Voice-over IP (VoIP), and satellite providers offer similar competing features as the telephone companies to both residential and businesses leading to further evolution of corporate identity have taken shape. Due to the nature of capital expenditure involved in the past, most telecommunications companies were government owned agencies or privately-owned mono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Multiplex System
Digital Multiplex System (DMS) is the name shared among several different telephony product lines from Nortel Networks for wireline and wireless operators. Among them are the DMS-1 (originally named the DMS-256) Rural/Urban digital loop carrier, the DMS-10 telephone switch, the DMS SuperNode family of telephone switches ( DMS-100, DMS-200, DMS-250, DMS-300, DMS-500, DMS-GSP, DMS-MSC, DMS-MTX), and the S/DMS optical transmission system. Exploratory development on the technology began at Northern Telecom's Bell Northern Research Labs in Ottawa, Ontario in 1971. The first Class 5 switch, the DMS-10, began service on 21 October 1977 in Fort White, Florida and the first toll switch (Class 4), the DMS-200, entered service in 1979 in Ottawa. The DMS-10 was the first commercially successful Class 5 digital switch in the North American market and had a profound impact on the industry. Of the numerous digital switching products introduced in the North American telephone market in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DMS-100
The DMS-100 is a member of the Digital Multiplex System (DMS) product line of telephone exchange switches manufactured by Northern Telecom. Designed during the 1970s and released in 1979, it can control 100,000 telephone lines. The purpose of the DMS-100 Switch is to provide local service and connections to the PSTN public telephone network. It is designed to deliver services over subscribers' telephone lines and trunks. It provides plain old telephone service (POTS), mobility management for cellular phone systems, sophisticated business services such as automatic call distribution (ACD), Integrated Services Digital Network (ISDN), and Meridian Digital Centrex (MDC), formerly called Integrated Business Network (IBN). It also provides Intelligent Network functions (AIN, CS1-R, ETSI INAP). It is used in countries throughout the world. There are also DMS-200 and DMS-250 variants for tandem switches. Much of the hardware used in the DMS-100, with the possible exception of the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5ESS Switch
The 5ESS Switching System is a Class 5 telephone electronic switching system developed by Western Electric for the American Telephone and Telegraph Company (AT&T) and the Bell System in the United States. It came into service in 1982 and the last unit was produced in 2003. History The 5ESS came to market as the Western Electric No. 5 ESS. It commenced service in Seneca, Illinois on March 25, 1982, and was destined to replace the Number One Electronic Switching System (1ESS and 1AESS) and other electromechanical systems in the 1980s and 1990s. The 5ESS was also used as a Class-4 telephone switch or as a hybrid Class 4/Class 5 switch in markets too small for the 4ESS. Approximately half of all US central offices are served by 5ESS switches. The 5ESS was also exported, and manufactured outside the US under license. The 5ESS–2000 version, introduced in the 1990s, increased the capacity of the switching module (SM), with more peripheral modules and more optical links per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicago
Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of United States cities by population, third-most populous city in the United States after New York City and Los Angeles. As the county seat, seat of Cook County, Illinois, Cook County, the List of the most populous counties in the United States, second-most populous county in the U.S., Chicago is the center of the Chicago metropolitan area, often colloquially called "Chicagoland" and home to 9.6 million residents. Located on the shore of Lake Michigan, Chicago was incorporated as a city in 1837 near a Chicago Portage, portage between the Great Lakes and the Mississippi River, Mississippi River watershed. It grew rapidly in the mid-19th century. In 1871, the Great Chicago Fire destroyed several square miles and left more than 100,000 homeless, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Electric
Western Electric Co., Inc. was an American electrical engineering and manufacturing company that operated from 1869 to 1996. A subsidiary of the AT&T Corporation for most of its lifespan, Western Electric was the primary manufacturer, supplier, and purchasing agent for all telephone equipment for the Bell System from 1881 until 1984, when Breakup of the Bell System, the Bell System was dismantled. Because the Bell System had a near-total monopoly over telephone service in the United States for much of the 20th century, Western Electric's equipment was widespread across the country. The company was responsible for many technological innovations, as well as developments in industrial management. History 19th century In 1856, George Shawk, a craftsman and telegraph maker, purchased an electrical engineering business in Cleveland, Ohio. In January 1869, Shawk had partnered with Enos M. Barton in the former Western Union repair shop of Cleveland, to manufacture burglar alarms, fire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Message Accounting
Automatic message accounting (AMA) provides detailed accounting for telephone calls. When direct distance dialing (DDD) was introduced in the US, message registers no longer sufficed for dialed telephone calls. The need to record the time and phone number of each long-distance call was met by electromechanical data processing equipment. Centralized AMA In centralized AMA (CAMA), the originating Class 5 telephone switches used automatic number identification (ANI) and multi-frequency (MF) signaling to send the originating and dialed telephone numbers to the Class 4 toll connecting office. The Class 4 office recorded this information with punched tape machines on long strips of paper, that had approximately the width of a hand. Each day a technician cut the paper tapes and sent them to the accounting center to be read and processed to generate customer telephone bills. Each punch recorder was responsible for 100 trunks, and its associated call identity indexer (CII) identified th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FCAPS
FCAPS is the ISO Telecommunications Management Network model and framework for network management. ''FCAPS'' is an acronym for fault, configuration, accounting, performance, security, the management categories into which the ISO model defines network management tasks. In non-billing organizations ''accounting'' is sometimes replaced with ''administration''. Background The ISO, under the direction of the OSI group, has created a network management model as the primary means for understanding the major functions of network management systems. The model in question is interchangeably called either the ''OSI network management model'' or ''ISO network management model'' so the full name could be the ''OSI/ISO network management model''. The comprehensive management of an organization's information technology (IT) infrastructure is a fundamental requirement. Employees and customers rely on IT services where availability and performance are mandated, and problems can be quickly id ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retronym
A retronym is a newer name for something that differentiates it from something else that is newer, similar, or seen in everyday life; thus, avoiding confusion between the two. Etymology The term ''retronym'', a neologism composed of the combining forms '' retro-'' (from Latin , "before") + '' -nym'' (from Greek , "name"), was coined by Frank Mankiewicz in 1980 and popularized by William Safire in '' The New York Times Magazine''. In 2000, '' The American Heritage Dictionary'' (4th edition) became the first major dictionary to include the word ''retronym''. Examples The global war from 1914 to 1918 was referred to at the time as the ''Great War''. However, after the subsequent global war erupted in 1939, the phrase ''Great War'' was gradually deprecated. The first came to be known as ''World War I'' and the second as ''World War II''. The first bicycles with two wheels of equal size were called " safety bicycles" because they were easier to handle than the then-dominant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circuit-switched
Circuit switching is a method of implementing a telecommunications network in which two network nodes establish a dedicated communications channel ( circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit. Circuit switching originated in analog telephone networks where the network created a dedicated circuit between two telephones for the duration of a telephone call. It contrasts with message switching and packet switching used in modern digital networks in which the trunklines between switching centres carry data between many different nodes in the form of data packets without dedicated circuits. Description The defining example of a circuit-switched network is the early analogue telephone network. When a call is made from one telephone to another, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twisted Pair
Twisted pair cabling is a type of communications cable in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted balanced pair, a twisted pair reduces electromagnetic radiation from the pair and crosstalk between neighboring pairs and improves rejection of external electromagnetic interference. It was invented by Alexander Graham Bell. For additional noise immunity, twisted-pair cabling may be shielded. Cable with shielding is known as shielded twisted pair (STP) and without as unshielded twisted pair (UTP). Explanation A twisted pair can be used as a balanced line, which as part of a balanced circuit can greatly reduce the effect of noise currents induced on the line by coupling of electric or magnetic fields. The idea is that the currents induced in each of the two wires are very nearly equal. The twisting ensures that the two wires are on average the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
