A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, R, S, T, U, W

ACR: attenuation to crosstalk ratio, a measure of how much more signal than noise exists in the link, by comparing the attenuated signal from one pair at the receiver to the crosstalk induced in the same pair.

Adapters: a type of balun that physically allows one connector to mate to another.

American wire gage (AWG): an American system of defining the size of copper wire.

Analog: an electrical signal that carries information in a continuously varying format.

ANSI: American National Standards Institute, oversees voluntary standards in the USA.

Attenuation: the reduction of signal strength over distance.

Backbone: cable that connects communications closets, entrance facilities and buildings.

Balanced transmission: sending signals of opposite polarity on each wire in a pair to maximize bandwidth and minimize interference. Used with all UTP cable.

Balun: a device that adapts one cabling type to another, including physical layout, impedance and connecting balanced to unbalanced cables.

Bandwidth: the frequency spectrum required or provided by communications networks.

Baud: for phone modems, it refers to the data rate, but in networks, it is the actual modulation rate which may not be the same as the data rate if encoding schemes are used.

Bend radius: minimum radius a cable can be bent without permanent damage.

Bit: a single piece of digital information, a "1" or "0".

Block: devices used for interconnection of cables.

Bonding: a permanent electrical connection.

Bridge: a device that connects two or more sets of telephone wires.

Bus: a network where all computers are connected by a single (usually coax) cable. Bus architecture can also be implemented with a hub and star configuration.

Cable tray: a channel system used to hold and support communications cables.

Capacitance: the ability of a conductor to store charge

Category 3: the UTP cable specified for signals up to 16 MHz. But commonly used for telephones.

Category 4: the UTP cable specified for signals up to 20 MHz, but not commonly used for structured wiring systems.

Category 5: the UTP cable specified for signals up to 100 MHz, commonly used for all LANs.

CATV: community antenna television, usually delivered by coax cable or HFC(hybrid fiber-coax) networks.

CCTV: closed circuit television, commonly used for security.

Client: the computer that operates in a network using programs and data stored in a server.

Coax: a type of cable that uses a central conductor, insulation, outer conductor/shield and jacket, used for high frequency communications like CCTV or CATV.

Conduit: special pipe used to carry cables. May be metal or plastic, solid or flexible.

Connector: the attachment on the end of a cable that allows interconnection to other cables.

Crimper: a tool used to install IDC plugs on cable.

Crossed pair: a pair of wires in a UTP cable that have two pairs cross-connected in error.

CSMA/CD: carrier sensing multiple access / collision detection, the protocol of Ethernet and other networks using bus or star architecture, that controls access to the LAN.

Current loop: transmission using variable current to carry information, like a simple analog telephone.

Delay skew: the maximum difference of propagation time in all pairs of a cable.

Dial tone: the tone heard in a phone when the receiver is picked up, indicating the line is available for dialing.

Dielectric: an insulator, used to protect copper wires in cable.

Digital: signals where the information is in the form of digital bits.

DTMF: dual tone multifrequency, or tone dialing used on modern phones, where discrete tones indicate numbers.

EIA/TIA 568 standard: a voluntary standard developed by vendors to insure interoperability of equipment used on network cabling.

EIA/TIA: Electronics Industry Association/Telecommunications Industry Association, a vendor-based group that writes interoperability standards for communications and electronics.

EL-FEXT:

ESCON: mainframe to peripheral network on fiber developed by IBM.

Ethernet: a 10 MB/s LAN based on bus or hub architecture. Most widely use LAN.

FCC: Federal Communications Commission, oversees all communications issues in the USA>

Firestop: restore a fire rated partition to it's fire rating after penetration with cabling,

Fishtape: semi-flexible rod used to retrieve cables or pull line.

Ground loop: the flow of current caused by unequal ground potentials.

Ground: a connection between a circuit or equipment and the earth.

Headend: the main distribution point in a CATV system.

Horizontal crossconnect: connection of horizontal wiring to other equipment or cabling.

Horizontal: cable that runs from a device to the communications closet.

Host: large computer used with terminals, usually a mainframe.

Hub: a switch used to connect computers in a star network.

IEC: International Electrotechnical Committee, oversees international communications standards.

IEEE: Institute of Electrical and Electronics Engineers, professional society that oversees most network standards.

Impedance matching devices: a type of balun that matches impedance between tow cables.

Impedance: the AC resistance

Insulation displacement connection (IDC): connecting wires by inserting or crimping cable into metal contacts that cut through the insulation, making contact with the wires.

Intermediate cross connect: connection point in the backbone cable between the main cross connect and the telecommunications closet

Internet: a worldwide network of computers that allows communications from computers.

ISO: International Standards Organization, oversees international standards.

Jacket: the outer protective covering of a cable.

J-hook: a hook shaped like the letter "J" used to suspend cables.

Key system: a simple multiline phone system that allows each user to select from several lines.

LAN: local area network, a group of computers and peripherals set up to communicate with each other.

Local loop: the interconnection of telephone central offices in a small region.

Loop resistance: measurement of the resistance of both wires in a pair measured from one end with the other end shorted.

Main cross connect: the connection point between building entrance, backbone and equipment cables.

Mainfame: large computer used to store and process massive amounts of data.

Mesh grip (aka Kellums grip): a grip made of wire mesh that grips the jacket of a cable for pulling.

Messenger cable: the aerial cable used to attach communications cable that has no strength member of its own.

Modular 8: the proper name for the 8 pin connector used in EIA/TIA 568 standard, commonly called the RJ-45.

Modular jack: a female connector for wall or panel installation, mates with modular plugs.

Modular plug: a standard connector used with wire, with 4 to 10 contacts, to mate cables with modular jacks.

NEC: National Electrical Code, written by NFPA, sets standards for fire protection for construction.

Network interface (NI): the demarcation point where the public network connects to a private (commercial or residential) network.

NEXT: near end crosstalk, measure of interference between pairs in UTP cable.

NFPA: National Fire Protection Association, which writes the NEC.

NIC: network interface card, used to interface computers to networks.

NIST: National Institute of Standards and Technology, establishes primary standards in the USA.

Nominal velocity of propagation (NVP): that speed of signal travel in the cable, expressed relative to the speed of light.

NOS, network operating system: the software that allows computers on a network to share data and program files.

Optical fiber: glass or plastic strands that can carry communications signals.

Patch panel: a crossconnection using jacks and patchcords to interconnect cables.

Plenum: the air carrying portion of a heating or air conditioning system that can be used for running communications cables. Also a type of cable used in plenums, specially rated by the NEC.

POTS: plain old telephone service.

Power Sum NEXT: Near end crosstalk tested with all pairs but one energized to find the total amount of crosstalk caused by simultaneous use of all pairs for communication.

Pulse dialing: old style phone dialing that works by making and breaking the current loop a number of times to indicate the number dialled.

Punch down tool: tool used to connect wire to IDC connections in punch down blocks.

Punch-down block: a connection block incorporating insulation displacement connections for interconnecting copper wires with a special insertion tool.

Return loss: reflection from an impedance mismatch in a copper cable.

Reversed pair: a pair of wires in a UTP cable that have the two wires cross-connected in error.

Ring: one conductor in a phone line, connected to the "Ring" of the contact on old-fashioned phone plugs.

Ring: a network where computers are connected in series to form a ring. Each computer in turn has an opportunity to use the network.

RJ-45: a modular 8 pin connector, actually referring to a specific telephone application, but usually referring to the connector used in EIA/TIA 568 standard.

ScTP: screened twisted pair cable, UTP cable with a outer shield under the jacket to prevent interference.

Server: the center of a network where programs and data are stored.

Shorted pair: a pair of wires in a UTP cable that are electrically connected in error.

Split pair: a pair of wires in a UTP cable that have the two wires of two different pairs cross-connected in error.

Star: a network where all the computers are connected to a central hub or server.

STP: shielded twisted pair cable, where each pair has a metallic shield to prevent interference.

Structured cabling: a method of installing cable per industry standards to allow interoperability among vendors and upgrades.

Subscriber loop: connection of the end-user to the local central office telephone switch.

Take off: reading drawings of a layout to get cable plant layout.

Telecommunications closet: location inside a building for interconnection of backbone and horizontal cables.

Telegraph: earliest form of long-distance communications, using coded letters.

Telephone switch: a device that connects telephones together when signalled by dialing.

Telephone: a voice instrument for communications.

Time domain reflectometer (TDR): a testing device used for cable that operates like radar to find length, shorts or opens, and impedance mismatches.

Tip: one conductor in a phone line, connected to the "Tip" of the old-fashioned phone plug.

Token Ring: a ring architecture LAN developed by IBM. 4 MB/s and 16 MB/s versions are used.

Tone dialing: used on modern phones, where discrete tones indicate numbers.

Topology: the architecture or layout of a network, eg. bus, ring, star.

USOC: Uniform Service Order Code, a UTP wiring scheme that allows 6 pin plugs to be used in 8 pin jacks for telephone use.

UTP: unshielded twisted pair cable, comprised of four pairs of conductors carefully manufacturer to preserve frequency characteristics.

Wire mapping: confirming the proper connections of all four pairs.

Wireless: sending communications over radio waves.

Work area outlet: the outlet at the end of the horizontal cabling where equipment is connected with a patchcord.

Work area: the location of the equipment connected to horizontal cabling.

World Wide Web: the graphical communication network operating over the Internet.