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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 are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Coil
Heat coils, also known as ''protectors'', ''bugs'' or ''carbons'' serve as a surge protector between the telephone exchange and outside plant. They are commonly the last point of appearance for a telephone circuit before it leaves the office, for example on the outside plant side of the main distribution frame. On some competitive local exchange carrier circuits there are two heat coils, the extra one being at the point of interface between their circuit and where the incumbent local exchange carrier or Regional Bell Operating Company receives it. Their primary purpose is to protect central office equipment from surges of high voltage. If a surge comes down the line it will melt the connection between the central office and outside plant sides, as in a fuse Fuse or FUSE may refer to: Devices * Fuse (electrical), a device used in electrical systems to protect against excessive current ** Fuse (automotive), a class of fuses for vehicles * Fuse (hydraulic), a device used in hydra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 the goal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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), they are used to 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 fulfillment, inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 (provincial electoral district), a provincial electoral district in British Columbia India *Kingsway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, 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'': low-density polyethylene is extruded using high pressure () and high temperature (), while high-density polyethylene is extruded using low pressure () and low temperature (). Polyethylene is usually thermoplastic, but it can be modified to become thermosetting instead, for example, in cross-linked polyethylene. History Polyethylene was first synthesized by the German chemist Hans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twisted Pair
Twisted pair cabling is a type of wiring used for communications 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 ave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Wrap
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 technologies since it allows for complex assemblies to be produced by automated equipment, but then easily repaired or modified by hand. Wire wrap construction can produce assemblies which are more reliable than printe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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