Term
| 1 gigabit per second (Gbps) |
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Definition
| 1,000,000,000 bits per second. |
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Term
| 1 kilobit per second (Kbps) |
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Definition
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Term
| 1 megabit per second (Mbps) |
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Definition
| 1,000,000 bits per second. |
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Term
| 1 terabit per second (Tbps) |
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Definition
| 1,000,000,000,000 bits per second. |
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Term
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Definition
| Part of an organization’s cross-connect facilities, a type of punch-down block designed to terminate Cat 5 or better twisted pair wires. |
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Term
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Definition
| UTP supplied by a telecommunications carrier that contains 100 wire pairs. |
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Term
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Definition
| An IEEE Physical layer standard for achieving a maximum of 10-Mbps throughput over coaxial copper cable. Thicknet is also known as 10Base-5. Its maximum segment length is 500 meters, and it relies on a bus topology. |
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Term
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Definition
| An IEEE Physical layer standard for achieving 10-Mbps throughput over coaxial copper cable. Thinnet is also known as 10Base-2. Its maximum segment length is 185 meters, and it relies on a bus topology. |
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Term
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Definition
| UTP supplied by a telecommunications carrier that contains 25 wire pairs. |
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Term
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Definition
| Part of an organization’s cross-connect facilities, a type of punch-down block used for many years to terminate telephone circuits. It does not meet Cat 5 or better standards, and so it is infrequently used on data networks. |
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Term
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Definition
| EMI interference induced on one cable by signals traveling over a nearby cable. |
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Term
| AM (amplitude modulation) |
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Definition
| A modulation technique in which the amplitude of the carrier signal is modified by the application of a data signal. |
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Term
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Definition
| A device that boosts, or strengthens, an analog signal. |
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Term
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Definition
| A measure of a signal’s strength. |
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Term
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Definition
| A signal that uses variable voltage to create continuous waves, resulting in an inexact transmission. |
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Term
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Definition
| The extent to which a signal has weakened after traveling a given distance. |
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Term
| AWG (American Wire Gauge) |
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Definition
A standard rating that indicates the diameter of a wire, such
as the conducting core of a coaxial cable. |
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Term
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Definition
| A measure of the difference between the highest and lowest frequencies that a medium can transmit. |
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Term
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Definition
| A form of transmission in which digital signals are sent through direct current pulses applied to a wire. This direct current requires exclusive use of the wire’s capacity, so baseband systems can transmit only one signal, or one channel, at a time. Every device on a baseband system shares a single channel. |
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Term
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Definition
| The radius of the maximum arc into which you can loop a cable before you will cause data transmission errors. Generally, a twisted pair cable’s bend radius is equal to or greater than four times the diameter of the cable. |
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Term
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Definition
| A system founded on using 1s and 0s to encode information. |
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Term
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Definition
| A bit equals a single pulse in the digital encoding system. It may have only one of two values: 0 or 1. |
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Term
| BNC (Bayonet Neill-Concelman, or British Naval Connector) |
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Definition
| A standard for coaxial cable connectors named after its coupling method and its inventors. |
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Term
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Definition
| A coaxial cable connector type that uses a twist-and-lock (or bayonet) style of coupling. It may be used with several coaxial cable types, including RG-6 and RG-59. |
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Term
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Definition
| A braided metal shielding used to insulate some types of coaxial cable. |
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Term
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Definition
| A form of transmission in which signals are modulated as radiofrequency analog pulses with different frequency ranges. Unlike baseband, broadband technology does not involve binary encoding. The use of multiple frequencies enables a broadband system to operate over several channels and, therefore, carry much more data than a baseband system. |
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Term
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Definition
| A transmission that involves one transmitter and multiple, undefined receivers. |
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Term
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Definition
Eight bits of information. In a digital signaling system, broadly speaking, one byte
carries one piece of information. |
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Term
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Definition
| The hardware that constitutes the enterprise-wide cabling system. |
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Term
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Definition
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Term
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Definition
| Abbreviation for the word category when describing a type of twisted pair cable. For example, Category 3 unshielded twisted pair cable may also be called Cat 3. |
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Term
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Definition
| A form of UTP that contains four wire pairs and can carry up to 10 Mbps, with a possible bandwidth of 16 MHz. Cat 3 has typically been used for 10-Mbps Ethernet or 4-Mbps token ring networks. Network administrators are gradually replacing Cat 3 cabling with Cat 5 to accommodate higher throughput. Less expensive than Cat 5. |
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Term
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Definition
| A form of UTP that contains four wire pairs and can support up to 16- Mbps throughput. Cat 4 may be used for 16-Mbps token ring or 10-Mbps Ethernet networks. It is guaranteed for data transmission up to 20 MHz and provides more protection against cross talk and attenuation than Cat 1, Cat 2, or Cat 3. |
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Term
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Definition
| A form of UTP that contains four wire pairs and supports up to 100- Mbps throughput and a 100-MHz signal rate. |
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Term
| Cat 5e (Enhanced Category 5) |
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Definition
| A higher-grade version of Cat 5 wiring that contains high- quality copper, offers a high twist ratio, and uses advanced methods for reducing cross talk. Enhanced Cat 5 can support a signaling rate of up to 350 MHz, more than triple the capability of regular Cat 5. |
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Term
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Definition
| A twisted pair cable that contains four wire pairs, each wrapped in foil insulation. Additional foil insulation covers the bundle of wire pairs, and a fire-resistant plastic sheath covers the second foil layer. The foil insulation provides excellent resistance to cross talk and enables Cat 6 to support a signaling rate of 250 MHz and at least six times the throughput supported by regular Cat 5. |
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Term
| Cat 6e (Enhanced Category 6) |
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Definition
| A higher-grade version of Cat 6 wiring that further reduces attenuation and cross talk and allows for potentially exceeding traditional network segment length limits. Cat 6e is capable of a 550-MHz signaling rate and can reliably transmit data at multi-gigabit per second rates. |
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Term
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Definition
| A twisted pair cable that contains multiple wire pairs, each separately shielded then surrounded by another layer of shielding within the jacket. Cat 7 can support up to a 1-GHz signal rate. But because of its extra layers, it is less flexible than other forms of twisted pair wiring. |
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Term
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Definition
| A distinct communication path between two or more nodes, much like a lane is a distinct transportation path on a freeway. Channels may be separated either logically (as in multiplexing) or physically (as when they are carried by separate wires). |
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Term
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Definition
| The glass or plastic shield around the core of a fiber-optic cable. Cladding reflects light back to the core in patterns that vary depending on the transmission mode. This reflection allows fiber to bend around corners without impairing the light-based signal. |
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Term
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Definition
| A type of cable that consists of a central metal conducting core, which might be solid or stranded and is often made of copper, surrounded by an insulator, a braided metal shielding, called braiding, and an outer cover, called the sheath or jacket. Coaxial cable, called “coax” for short, was the foundation for Ethernet networks in the 1980s. Today it’s used to connect cable Internet and cable TV systems. |
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Term
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Definition
| The pipeline used to contain and protect cabling. Conduit is usually made from metal. |
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Term
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Definition
| The pieces of hardware that connect the wire to the network device, be it a file server, workstation, switch, or printer. |
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Term
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Definition
| The central component of a cable designed to carry a signal. The core of a fiber-optic cable, for example, consists of one or several glass or plastic fibers. The core of a coaxial copper cable consists of one large or several small strands of copper. |
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Term
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Definition
| A twisted pair patch cable in which the termination locations of the transmit and receive wires on one end of the cable are reversed. |
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Term
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Definition
| A type of interference caused by signals traveling on nearby wire pairs infringing on another pair’s signal. |
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Term
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Definition
| A type of connector with nine pins that’s commonly used in serial communication that conforms to the RS-232 standard. |
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Term
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Definition
| A type of connector with 25 pins that’s commonly used in serial communication that conforms to the RS-232 standard. |
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Term
| DCE (data circuit-terminating equipment) |
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Definition
| A device, such as a multiplexer or modem, that processes signals. DCE supplies a clock signal to synchronize transmission between DTE and DCE. |
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Term
| demarcation point (demarc) |
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Definition
| The point of division between a telecommunications service carrier’s network and a building’s internal network. |
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Term
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Definition
| A device that separates multiplexed signals once they are received and regenerates them in their original form. |
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Term
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Definition
As opposed to analog signals, digital signals are composed of pulses that can have a
value of only 1 or 0. |
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Term
| DTE (data terminal equipment) |
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Definition
| Any end-user device, such as a workstation, terminal (essentially a monitor with little or no independent data-processing capability), or a console (for example, the user interface for a router). |
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Term
| DWDM (dense wavelength division multiplexing) |
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Definition
| A multiplexing technique used over single-mode or multimode fiber-optic cable in which each signal is assigned a different wavelength for its carrier wave. In DWDM, little space exists between carrier waves in order to achieve extraordinary high capacity. |
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Term
| EMI (electromagnetic interference) |
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Definition
A type of interference that may be caused by motors,
power lines, televisions, copiers, fluorescent lights, or other sources of electrical activity. |
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Term
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Definition
| The facilities necessary for a service provider (whether it is a local phone company, Internet service provider, or long-distance carrier) to connect with another organization’s LAN or WAN. |
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Term
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Definition
| A connector used to terminate coaxial cable used for transmitting television and broadband cable signals. |
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Term
| FDM (frequency division multiplexing) |
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Definition
| A type of multiplexing that assigns a unique frequency band to each communications subchannel. Signals are modulated with different carrier frequencies, then multiplexed to simultaneously travel over a single channel. |
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Term
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Definition
| A short tube within a fiber-optic cable connector that encircles the fiber strand and keeps it properly aligned. |
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Term
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Definition
| A form of cable that contains one or several glass or plastic fibers in its core. Data is transmitted via pulsing light sent from a laser or light-emitting diode (LED) through the central fiber (or fibers). Fiber-optic cables offer significantly higher throughput than copper-based cables. They may be single-mode or multimode and typically use wave- division multiplexing to carry multiple signals. |
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Term
| FM (frequency modulation) |
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Definition
| A method of data modulation in which the frequency of the carrier signal is modified by the application of the data signal. |
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Term
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Definition
| The number of times that a signal’s amplitude changes over a fixed period of time, expressed in cycles per second, or hertz (Hz). |
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Term
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Definition
| A type of transmission in which signals may travel in both directions over a medium simultaneously. May also be called, simply, “duplex.” |
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Term
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Definition
| A type of transmission in which signals may travel in both directions over a medium, but in only one direction at a time. |
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Term
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Definition
| A measure of frequency equivalent to the number of amplitude cycles per second. |
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Term
| IDF (intermediate distribution frame) |
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Definition
| A junction point between the MDF and concentrations of fewer connections—for example, those that terminate in a telecommunications closet. |
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Term
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Definition
| The resistance that contributes to controlling an electrical signal. Impedance is measured in ohms. |
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Term
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Definition
| The delay between the transmission of a signal and its receipt. |
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Term
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Definition
| A connector used with single-mode or multimode fiber-optic cable. |
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Term
| MDF (main distribution frame) |
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Definition
| Also known as the main cross-connect, the first point of interconnection between an organization’s LAN or WAN and a service provider’s facility. |
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Term
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Definition
| A device that enables networks or segments using different media to interconnect and exchange signals. |
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Term
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Definition
| A type of fiber-optic cable that contains a core with a diameter between 50 and 100 microns, through which many pulses of light generated by a light- emitting diode (LED) travel at different angles. |
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Term
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Definition
| A device that modulates analog signals into digital signals at the transmitting end for transmission over telephone lines, and demodulates digital signals into analog signals at the receiving end. |
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Term
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Definition
| A technique for formatting signals in which one property of a simple carrier wave is modified by the addition of a data signal during transmission. |
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Term
| MT-RJ (mechanical transfer-registered jack) |
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Definition
| A connector used with single-mode or multimode fiber-optic cable. |
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Term
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Definition
| A device that separates a medium into multiple channels and issues signals to each of those subchannels. |
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Term
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Definition
| A form of transmission that allows multiple signals to travel simultaneously over one medium. |
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Term
| NEXT (near end cross talk) |
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Definition
| Cross talk, or the impingement of the signal carried by one wire onto a nearby wire, that occurs between wire pairs near the source of a signal. |
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Term
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Definition
| The unwanted signals, or interference, from sources near network cabling, such as electrical motors, power lines, and radar. |
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Term
| nonbroadcast point-to-multipoint transmission |
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Definition
| A communications arrangement in which a single transmitter issues signals to multiple, defined recipients. |
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Term
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Definition
| The degradation of a light signal on a fiber-optic network. |
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Term
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Definition
| The nondata information that must accompany data in order for a signal to be properly routed and interpreted by the network. |
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Term
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Definition
| A relatively short section (usually between 3 and 25 feet) of cabling with connectors on both ends. |
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Term
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Definition
| A wall-mounted panel of data receptors into which cross-connect patch cables from the punch-down block are inserted. |
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Term
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Definition
| A point or stage in a wave’s progress over time. |
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Term
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Definition
| The area above the ceiling tile or below the subfloor in a building. |
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Term
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Definition
| A data transmission that involves one transmitter and one receiver. |
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Term
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Definition
| A communications arrangement in which one transmitter issues signals to multiple receivers. The receivers may be undefined, as in a broadcast transmission, or defined, as in a nonbroadcast transmission. |
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Term
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Definition
| A network segment that contains end nodes, such as workstations. |
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Term
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Definition
| A panel of data receptors into which twisted pair wire is inserted, or punched down, to complete a circuit. |
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Term
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Definition
| The process of retransmitting a digital signal. Regeneration, unlike amplification, repeats the pure signal, with none of the noise it has accumulated. |
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Term
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Definition
| A device used to regenerate a signal. |
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Term
| RFI (radiofrequency interference) |
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Definition
| A kind of interference that may be generated by broadcast signals from radio or TV towers. |
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Term
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Definition
| A type of coaxial cable with an impedance of 75 ohms and that contains an 18 AWG core conductor. RG-6 is used for television, satellite, and broadband cable connections. |
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Term
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Definition
| A type of coaxial cable characterized by a 50-ohm impedance and a 10 AWG core. RG-8 provided the medium for the first Ethernet networks, which followed the now- obsolete 10Base-5 standard. |
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Term
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Definition
| A type of coaxial cable characterized by a 50-ohm impedance and a 24 AWG core. RG-58 was a popular medium for Ethernet LANs in the 1980s, used for the now-obsolete 10Base-2 standard. |
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Term
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Definition
| A type of coaxial cable characterized by a 75-ohm impedance and a 20 or 22 AWG core, usually made of braided copper. Less expensive but suffering greater attenuation than the more common RG-6 coax, RG-59 is used for relatively short connections. |
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Term
| RJ-11 (registered jack 11) |
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Definition
| The standard connector used with unshielded twisted pair cabling (usually Cat 3 or Level 1) to connect analog telephones. |
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Term
| RJ-45 (registered jack 45) |
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Definition
| The standard connector used with shielded twisted pair and unshielded twisted pair cabling. |
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Term
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Definition
| A type of cable in which the terminations on one end are exactly the reverse of the terminations on the other end. It is used for serial connections between routers and consoles or other interfaces. |
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Term
| RS-232 (Recommended Standard 232) |
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Definition
A Physical layer standard for serial communications,
as defined by EIA/TIA. |
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Term
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Definition
| The length of time it takes for a packet to go from sender to receiver, then back from receiver to sender. RTT is usually measured in milliseconds. |
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Term
| SC (subscriber connector or standard connector) |
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Definition
| A connector used with single-mode or multimode fiber-optic cable. |
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Term
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Definition
| A style of data transmission in which the pulses that represent bits follow one another along a single transmission line. In other words, they are issued sequentially, not simultaneously. |
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Term
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Definition
| A cable, such as an RS-232 type, that permits serial data transmission. |
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Term
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Definition
| The outer cover, or jacket, of a cable. |
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Term
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Definition
| A type of transmission in which signals may travel in only one direction over a medium. |
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Term
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Definition
| A type of fiber-optic cable with a narrow core that carries light pulses along a single path data from one end of the cable to the other end. Data can be transmitted faster and for longer distances on single-mode fiber than on multimode fiber. However, single-mode fiber is more expensive. |
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Term
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Definition
| A connector used with single-mode or multimode fiber-optic cable. |
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Term
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Definition
| A method of multiplexing in which each node on a network is assigned a separate time slot for transmission, based on the node’s priority and need. |
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Term
| STP (shielded twisted pair) |
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Definition
| A type of cable containing twisted-wire pairs that are not only individually insulated, but also surrounded by a shielding made of a metallic substance such as foil. |
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Term
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Definition
| A twisted pair patch cable in which the wire terminations in both connectors follow the same scheme. |
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Term
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Definition
| A method for uniform, enterprise-wide, multivendor cabling systems specified by the TIA/EIA 568 Commercial Building Wiring Standard. Structured cabling is based on a hierarchical design using a high-speed backbone. |
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Term
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Definition
| One of many distinct communication paths established when a channel is multiplexed or modulated. |
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Term
| TDM (time division multiplexing) |
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Definition
| A method of multiplexing that assigns a time slot in the flow of communications to every node on the network and, in that time slot, carries data from that node. |
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Term
| telecommunications closet |
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Definition
| Also known as a “telco room,” the space that contains connectivity for groups of workstations in a defined area, plus cross-connections to IDFs or, in smaller organizations, an MDF. Large organizations may have several telecommunications closets per floor, but the TIA/EIA standard specifies at least one per floor. |
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Term
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Definition
| The amount of data that a medium can transmit during a given period of time. Throughput is usually measured in megabits (1,000,000 bits) per second, or Mbps. The physical nature of every transmission media determines its potential throughput. |
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Term
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Definition
| A device that transmits and receives signals. |
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Term
|
Definition
| In networking, the application of data signals to a medium or the progress of data signals over a medium from one point to another. |
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Term
|
Definition
| To issue signals to the network medium. |
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Term
|
Definition
| The number of twists per meter or foot in a twisted pair cable. |
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Term
|
Definition
| A type of cable similar to telephone wiring that consists of color-coded pairs of insulated copper wires, each with a diameter of 0.4 to 0.8 mm, twisted around each other and encased in plastic coating. |
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Term
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Definition
| A network segment that does not contain end nodes, such as workstations. Unpopulated segments are also called link segments. |
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Term
| UTP (unshielded twisted pair) |
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Definition
| A type of cabling that consists of one or more insulated wire pairs encased in a plastic sheath. As its name implies, UTP does not contain additional shielding for the twisted pairs. As a result, UTP is both less expensive and less resistant to noise than STP. |
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Term
|
Definition
| Part of a network’s backbone that supplies connectivity between a building’s floors. For example, vertical cross-connects might connect an MDF and an IDF or IDFs and telecommunications closets within a building. |
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Term
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Definition
| The measurement used to describe the degree of pressure an electrical current exerts on a conductor. |
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Term
|
Definition
| The pressure (sometimes informally referred to as the strength) of an electrical current. |
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Term
|
Definition
The distance between corresponding points on a wave’s cycle. Wavelength is
inversely proportional to frequency. |
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Term
| WDM (wavelength division multiplexing) |
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Definition
| A multiplexing technique in which each signal on a fiber-optic cable is assigned a different wavelength, which equates to its own subchannel. Each wavelength is modulated with a data signal. In this manner, multiple signals can be simultaneously transmitted in the same direction over a length of fiber. |
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