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Intermediate Distribution Frame
An intermediate distribution frame (IDF) is a distribution frame in a central office or customer premises, which cross connects the user cable media to individual user line circuits and may serve as a distribution point for multipair cables from the main distribution frame (MDF) or combined distribution frame (CDF) to individual cables connected to equipment in areas remote from these frames. IDFs are used for telephone exchange central office, customer-premises equipment, wide area network (WAN), and local area network (LAN) environments, among others. In central office environments the IDF may contain circuit termination equipment from various auxiliary components. In WAN and LAN environments IDFs can hold devices of different types including backup systems ( hard drives or other media as self-contained, or as RAIDs, CD-ROMs, etc.), networking ( switches, hubs, routers), and connections (fiber optics An optical fiber, or optical fibre, is a flexible glass or plast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Distribution Frame
In telecommunications, a distribution frame is a passive device which terminates cables, allowing arbitrary interconnections to be made. For example, the Main Distribution Frame (MDF) located at a telephone exchange, telephone central office terminates the cables leading to subscribers on the one hand, and cables leading to active equipment (such as DSLAMs and telephone switches) on the other. Service is provided to a subscriber by manually wiring a twisted pair (called a jumper wire) between the telephone line and the relevant DSL or Plain old telephone service, POTS line circuit. In broadcast engineering, a distribution frame is a location within an apparatus room through which all signals (Sound, audio, video, or data) pass, with the ability to arbitrarily route and connect sources and destinations between studios and other internal and external points. Connections can either be Solder, soldered, or made using terminal blocks. Because the frame may carry live broadcast signal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Hard Disk Drive
A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating hard disk drive platter, platters coated with magnetic material. The platters are paired with disk read-and-write head, magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual Block (data storage), blocks of data can be stored and retrieved in any order. HDDs are a type of non-volatile storage, retaining stored data when powered off. Modern HDDs are typically in the form of a small disk enclosure, rectangular box. Hard disk drives were introduced by IBM in 1956, and were the dominant secondary storage device for History of general-purpose CPUs, general-purpose computers beginning in the early 1960s. HDDs maintained this position into the modern er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Coaxial Cable
Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulator (electricity), insulating material); many coaxial cables also have a protective outer sheath or jacket. The term ''coaxial'' refers to the inner conductor and the outer shield sharing a geometric axis. Coaxial cable is a type of transmission line, used to carry high-frequency Signal, electrical signals with low losses. It is used in such applications as telephone trunk lines, Internet access, broadband internet networking cables, high-speed computer bus (computing), data buses, cable television signals, and connecting Transmitter, radio transmitters and Radio receiver, receivers to their Antenna (radio), antennas. It differs from other shielded cables because the dimensions of the cable and connectors are controlled to give a precise, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Optical Fiber
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher Bandwidth (computing), bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less Attenuation, loss and are immune to electromagnetic interference. Fibers are also used for illumination (lighting), illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers. Glass optical fibers are typically made by Drawing (manufacturing), drawing, while plastic fibers can be made either by drawing or by extrusion. Optical fibers typically incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ethernet Hub
An Ethernet hub, active hub, network hub, repeater hub, multiport repeater, or simply hub is a network hardware device for connecting multiple Ethernet devices together and making them act as a single network segment. It has multiple input/output (I/O) ports, in which a signal introduced at the input of any Computer port (hardware), port appears at the output of every port except the original incoming. A hub works at the physical layer. A repeater hub also participates in collision detection, forwarding a jam signal to all ports if it detects a collision (telecommunications), collision. In addition to standard 8P8C ("RJ45") ports, some hubs may also come with a BNC connector, BNC or an Attachment Unit Interface (AUI) connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. Hubs are now largely obsolete, having been replaced by network switches except in very old installations or #Uses, specialized applications. As of 2011, connecting network segments by repe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Network Switch
A network switch (also called switching hub, bridging hub, Ethernet switch, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Switches for Ethernet are the most common form of network switch. The first MAC Bridge was invented in 1983 by Mark Kempf, an engineer in the Networking Advanced Development group of Digital Equipment Corporation. The first 2 port Bridge product (LANBridge 100) was introduced by that company shortly after. The company subsequently produced multi-port switches for both Ethernet and FDDI such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Computer Network
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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CD-ROM
A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains computer data storage, data computers can read, but not write or erase. Some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player, while data (such as software or digital video) is only usable on a computer (such as ISO 9660 format PC CD-ROMs). During the 1990s and early 2000s, CD-ROMs were popularly used to distribute software and data for computers and fifth generation video game consoles. DVDs as well as downloading started to replace CD-ROMs in these roles starting in the early 2000s, and the use of CD-ROMs for commercial software is now rare. History The earliest theoretical work on optical disc storage was done by independent researchers in the United States including David Paul Gregg (1958) and James Russell (inventor), James Russel (1965–1975). In particular, Gregg's paten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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RAID
RAID (; redundant array of inexpensive disks or redundant array of independent disks) is a data storage virtualization technology that combines multiple physical Computer data storage, data storage components into one or more logical units for the purposes of data redundancy, performance improvement, or both. This is in contrast to the previous concept of highly reliable mainframe disk drives known as ''single large expensive disk'' (''SLED''). Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy (engineering), redundancy and performance. The different schemes, or data distribution layouts, are named by the word "RAID" followed by a number, for example RAID 0 or RAID 1. Each scheme, or RAID level, provides a different balance among the key goals: reliability engineering, reliability, availability, computer performance, performance, and computer data storage#Capacity, capacity. RAID levels ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Backup
In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "wikt:back up, back up", whereas the noun and adjective form is "wikt:backup, backup". Backups can be used to data recovery, recover data after its loss from File deletion, data deletion or Data corruption, corruption, or to recover data from an earlier time. Backups provide a simple form of IT disaster recovery; however not all backup systems are able to reconstitute a computer system or other complex configuration such as a computer cluster, active directory server, or database server. A backup system contains at least one copy of all data considered worth saving. The computer data storage, data storage requirements can be large. An information repository model may be used to provide structure to this storage. There are different types of data stor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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, enabling telephone calls between subscribers. The term "central office" can also refer to a central location for fiber optic equipment for a fiber internet provider. In historical perspective, telecommunication terminology has evolved with time. The term ''telephone exchange'' is often used synonymously with ''central office'', a Bell System term. A central office is defined as the telephone switch controlling connections for one or more central office prefixes. However, it also often denotes the building used to house the inside plant equipment for multiple telephone exchange areas. In North America, the term ''wire center'' may be used to denote a central office location, indicating a facility that provides a telephone with a dial tone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |