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Main Distribution Frame
In telephony, a main distribution frame (MDF or main frame) is a signal distribution frame for connecting equipment (inside plant) to cables and subscriber carrier equipment ( outside plant). Overview The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires at the MDF. All cable copper pairs supplying services through user telephone lines are terminated at the MDF and distributed through the MDF to equipment within the local exchange e.g. repeaters and DSLAM. Cables to intermediate distribution frames (IDF) terminate at the MDF. Trunk cables may terminate on the same MDF or on a separate trunk main distribution frame (TMDF). Like other distribution frames the MDF provides flexibility in assigning facilities, at lower cost and higher capacity than a patch panel. The most common kind of large MDF is a long steel rack accessible from both sides. On one side, termination blocks a ...
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Electrical Wiring
Electrical wiring is an electrical installation of Electrical cable, cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure. Wiring is subject to safety standards for design and installation. Allowable wire and electrical cable, cable types and sizes are specified according to the circuit operating voltage and electric current capability, with further restrictions on the environmental conditions, such as ambient temperature range, moisture levels, and exposure to sunlight and chemicals. Associated circuit protection, control, and distribution devices within a building's wiring system are subject to voltage, current, and functional specifications. Wiring safety codes vary by locality, country, or region. The International Electrotechnical Commission (IEC) is attempting to harmonise wiring standards among member countries, but significant variations in design and installation requirements still exist. Wiring methods ...
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Distributed Switching
Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations * Probability distribution, the probability of a particular value or value range of a variable ** Cumulative distribution function, in which the probability of being no greater than a particular value is a function of that value * Frequency distribution, a list of the values recorded in a sample * Inner distribution, and outer distribution, in coding theory *Distribution (differential geometry), a subset of the tangent bundle of a manifold * Distributed parameter system, systems that have an infinite-dimensional state-space * Distribution of terms, a situation in which all members of a category are accounted for * Distributivity, a property of binary operations that generalises the distributive law from elementary algebra * Distribution (number theory) *Distribution problems, a common type of problems in combinatorics where th ...
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Operations Support Systems
Operations support systems (OSS), operational support systems in British usage, or Operation System (OpS) in NTT are computer systems used by telecommunications service providers to manage their networks (e.g., telephone networks). They support management functions such as network inventory, service provisioning, network configuration and fault management. Together with business support systems (BSS), operations support systems support various end-to-end telecommunication services. BSS and OSS have their own data and service responsibilities. The two systems together are often abbreviated OSS/BSS, BSS/OSS or simply B/OSS. The acronym OSS is also used in a singular form to refer to all the Operations Support Systems viewed as a whole system. Different subdivisions of OSS have been proposed by the TM Forum, industrial research labs, or OSS vendors. In general, an OSS covers at least the following five functions: * Network management systems * Service delivery *Service fulfillme ...
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COSMOS (Telecommunications)
COSMOS (Computer System for Main Frame Operations) was a record-keeping system for main distribution frames (MDFs) in the Bell System, the American Bell Telephone Company and then, subsequently, AT&T–led system which provided telephone services to much of the United States and Canada from 1977 to 1984. COSMOS was introduced in the 1970s after MDFs were found to be congested in large urban telephone exchange A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits ...s. It assigns terminals so jumpers need not be so long, thus leaving more space on the shelves. COSMOS also converts customer service orders into printed work orders for staff who connect the jumpers. COSMOS orders are usually coordinated with RCMAC to ensure that translations match wiring. With good computer records, jum ...
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Kingsway Tunnels -JPP 7820 (14436555228)
Kingsway or King's Way may refer to: Places Australia *Kingsway, Glen Waverley, a shopping strip in Melbourne, Victoria Canada *Kingsway (Edmonton), a road in Edmonton, Alberta (aka Kingsway Avenue) *Kingsway (Vancouver), a road in Vancouver, British Columbia *The Kingsway, Toronto, a neighbourhood in Toronto, Ontario (aka Kingsway South) *The Kingsway, a segment of Sudbury Municipal Road 55, Sudbury, Ontario *Kingsway College, a Seventh-day Adventist boarding secondary school in Oshawa, Ontario *Kingsway Mall, a shopping centre in Edmonton, Alberta *Kingsway Village (Oshawa), a neighbourhood in Oshawa, Ontario *Burnaby—Kingsway, a federal electoral district in British Columbia between 1988 and 1997 *Lambton-Kingsway Junior Middle School, a public elementary school in Etobicoke, Ontario *Vancouver Kingsway, a federal electoral district in British Columbia *Vancouver-Kingsway, a provincial electoral district in British Columbia Gibraltar * Kingsway, Gibraltar, the main access ...
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Cross-linked Polyethylene
Cross-linked polyethylene, commonly abbreviated PEX, XPE or XLPE, is a form of polyethylene with cross-links. It is used predominantly in building services pipework systems, hydronic radiant heating and cooling systems, domestic water piping, insulation for high tension (high voltage) electrical cables, and baby play mats. It is also used for natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. PEX is an alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper tubing for use as residential water pipes. Properties Low-temperature impact strength, abrasion resistance and environmental stress cracking resistance can be increased significantly by crosslinking, whereas hardness and rigidity are somewhat reduced. Compared to thermoplastic polyethylene, PEX does not melt (analogous to elastomers) and is thermally resistant (over longer periods of up to 120 °C, for short periods without ele ...
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Polyethylene
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, cups, jars, etc.). , over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market. Many kinds of polyethylene are known, with most having the chemical formula (C2H4)''n''. PE is usually a mixture of similar polymers of ethylene, with various values of ''n''. It can be ''low-density'' or ''high-density'' and many variations thereof. Its properties can be modified further by crosslinking or copolymerization. All forms are nontoxic as well as chemically resilient, contributing to polyethylene's popularity as a multi-use plastic. However, polyethylene's chemical resilience also makes it a long-lived and decomposition-resistant pollutant when disposed of improperly. Being a h ...
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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 ...
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Punch Block
A punch-down block (also punchdown block, punch block, punchblock, quick-connect block and other variations) is a type of electrical connection often used in telephony. It is named because the solid copper wires are "punched down" into short open-ended slots which are a type of insulation-displacement connector. These slots, usually cut crosswise (not lengthwise) across an insulating plastic bar, contain two sharp metal blades which cut through the wire's insulation as it is punched down. These blades hold the wire in position and make the electrical contact with the wire as well. Overview A tool called a punch down tool is used to push the wire down firmly and properly into the slot. Some will automatically cut any excess wire off. The exact size and shape of the tool blade varies by manufacturer, which can cause problems for those working on existing installations, especially when there is a poorly documented mix of different brands. Punch-down blocks are a very quick and ...
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Wire Wrap
Close-up of a wire-wrap connection Typical wire wrap construction of crossbar_switch.html" ;"title="Bell System telephone crossbar switch">Bell System telephone crossbar switch. Some types of connection were soldered. Wire wrap is an electronic component assembly technique that was invented to wire telephone crossbar switches, and later adapted to construct electronic circuit boards. Electronic components mounted on an insulating board are interconnected by lengths of insulated wire run between their terminals, with the connections made by wrapping several turns of uninsulated sections of the wire around a component lead or a socket pin. Wires can be wrapped by hand or by machine, and can be hand-modified afterwards. It was popular for large-scale manufacturing in the 1960s and early 1970s, and continues today to be used for short runs and prototypes. The method eliminates the design and fabrication of a printed circuit board. Wire wrapping is unusual among other prototyping ...
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Soldering
Soldering (; ) is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creating a strong and durable joint. Soldering is commonly used in the electronics industry for the manufacture and repair of Printed circuit board, printed circuit boards (PCBs) and other electronic components. It is also used in plumbing and Metalworking, metalwork, as well as in the manufacture of jewelry and other decorative items. The solder used in the process can vary in composition, with different alloys used for different applications. Common solder alloys include tin-lead, tin-silver, and tin-copper, among others. Lead-free solder has also become more widely used in recent years due to health and environmental concerns associated with the use of lead. In addition to the type of solder used, the temperature and method of heating also p ...
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