Glossary B

Glossary B
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Back-end: Database Server for manipulating data.
Backbone: A facility (pathway, cable or conductors) between telecommunications closets, entrance facilities & equipment rooms within or between buildings.
Backbone Cabling: Cable & connecting hardware that comprise the main & intermediate cross-connects as well as cable runs that extend between telecommunications closets equipment rooms & entrance facilities
Backbone Raceway: That portion of the pathway system that permits the placing of main or high-volume cables between the entrance location & all cross-connect points within a building & between buildings.
Backbone Segment: A single segment that is located on the black plane of the network center hub.
Backup: Off-line copies of data for protection against system failures.
Backup Path: The unused pair of wires in the twisted pair cable used in a Token ring network. The backup path is designed to enable the network to continue to operate while a problem such as a faulty cable or MAU is being repaired.
Balanced Circuit: A circuit so arranged that the impressed voltages on each conductor of the pair are equal in magnitude, but opposite in polarity with respect to ground.
Balanced Line: A cable having two identical conductors which carry voltages opposite in polarity & equal in magnitude with respect to ground.
Balun: Derived from the terms “balanced” & “unbalanced”. It is an adapter that converts an unbalanced signal, e.g. 93 ohm coax to 100 ohm unshielded twisted pair.
Band Marking: A continuous circumferential band applied to a conductor at regular intervals for identification.
Bandwidth: The information carrying capacity of the fiber. The bandwidth for a given wavelength is the lowest frequency at which optical power has decreased by 3 dB, expressed in MHz-km. At frequencies higher than the recommended bandwidth, modal dispersion creates distortion making signals unreadable.
Baseband: A transmission technique that allows only one signal at a time to travel on a cable.
Baud: The measurement of signal changes per second. This is not necessarily equal to bits per second, as one signal change may represent several bits.
Baudot: Data-transmission code in which 5 bits represent 1 character. Letters or figure shifts enables 64 alphanumeric characters to be represented. Baudot is used in many teleprinter systems, with one start bit & 1.5 stop bits added.
Bayonet Neill-Corcelman: (BNC) A coax connector that is locked on by a quarter turn. Typically used on Thinnet.
BBS: See Bulletin Board System
BCC: See Block Check Character
Bend Loss: Signal loss that occurs due to beams of light escaping where the fiber is bent.
Bend Radius: The smallest bend a cable can withstand before the transmission is affected.
BER: See Bit Error Rate
Berkeley Internet Name Domain: (BIND) An early version of a DNS server developed by University of California at Berkeley. Most Internet hosts run a version of BIND.
Best Path: The optimal route through a wide area network. Routers use a routing protocol to determine the best sequence of links each packet should take in order to reach its destination with the lowest delay cost or other criteria.
Binary Numbering System: A two-state numbering system (bi=2) Represented on paper as a sequence of 1's & 0's.
BIND: See Berkeley Internet Name Domain
Binder: A tape or thread used for holding assembled cable components in place.
Bindery: NetWare database of user names, passwords, groups & accounting information.
Bisynchronous Transmission: (BSC) A byte or character oriented IBM communications protocol that has become an industry standard. It uses a defined set of control characters for synchronized transmission of binary coded data between stations in a data communications system.
Bit: A contraction of Binary digit. A BIT is the smallest element of information in a digital system that can have a on (yes) value or off (no) value.
Bit Error Rate: (BER) The ratio of received bits that are in error (relative to a specific amount of bits received): usually expressed as a number referenced to a power of 10
Bitnet: A Computer network devoted to academic use that provides e-mail & file transfer services using a store-and-forward protocol. It is based on the IBM Network Job Entry protocols. A more recent version of Bitnet (known as Bitnet-II) encapsulates the Bitnet protocol within OP packets.
Bits per second: (BPS) A term used to express the speed at which bits can be transmitted.
Block: A sequence of continuous data transmitted as a unit. Sometimes referred to as transmission block.
Block Check Character: (BCC) A bit pattern attached to the end of a transmission block for error detection purposes. Used primarily during synchronous transmission.
Block Framing Character: Characters used to mark the beginning & ending of a transmission block.
BNC: See Bayonet Neill-Corcelman
Bonding: The permanent joining of metallic parts to form an electrically conductive path which will assure electrical continuity & the capacity to conduct safely any current likely to be imposed on it.
Booster: A device or amplifier inserted into a line or cable to increase the voltage or signal.
Boot: A protective coating over a cable; wire or connector in addition to the normal jacket or insulation or a form placed around wire termination of a multi-contact connector to contain the liquid potting compound before it hardens.
Bounce: If you send e-mail & it fails to arrive at its intended recipient for any reason (incorrect user name, network failure, etc.), the message "bounces" & return to you. The subject line in a bounced message usually says something like: "Undeliverable mail" or "Message Undeliverable."
bps: See Bits per second
Braid: A group of textile or metallic filaments interwoven to form a tubular structure which may be applied over one or more wires, or flattened to form a strap.
Breakout: Multifiber cable constructed in a tight buffered design. Designed for ease of connecting & rugged applications for intra- or interbuilding requirements.
Bridge: Used to connect two separate local or remote networks of the same communication standard (i.e. Ethernet to Ethernet or Token Ring to Token Ring).
Broadband: A data transmission technique allowing multiple high speed signals to share the bandwidth of a single cable via frequency division multiplexing.
Broadcast: A packet delivery system that allows all host attached to the network to receive a copy of the sent packet.
Broadcast Domain: The complete set of uses to whom a broadcast frame is transmitted to, from an indicated end station. The boundaries of a broadcast domain are defined by routers.
Broadcast Storm: A LAN software failure mode caused by many stations on the network incorrectly replying to a broadcast packet with another broadcast packet. The result is an extremely high traffic load. A broadcast storm is usually caused by misconfigured network software.
Brouters: A network device that can perform the functions of both a bridge & a router.
BSC: See Bisynchronous Transmission
Buffer: A storage device. Commonly used to compensate for the differences in data rates or even timing when transmitting from one device to another. Also used to remove jitters. Or on a fiber optic, a layer of material, usually thermoplastic, applied in addition to the optical fiber coating, which provides protection from stress & handling.
Bulletin Board System: (BBS) A computer that typically provides e-mail services, file archives, & announcements of interest to the bulletin board system's operator (known as a sysop). BBSs started out as hobbies for computer enthusiasts, & were mostly accessible by modem. Recently, however, more & more BBSs are connecting to the Internet.
Bunch Strand: Conductors twisted together with the same lay & direction without regard to geometric pattern.
Bundle (Fiber Optic): A number of fibers grouped together, usually carrying a common signal.
Buried Cable: A cable installed directly in the earth without the use of underground conduit. Also called "direct burial cable"
Bus: A LAN topology. All devices are linked in a string or line (or hooked in series).
Bus-bar Wire: Uninsulated tinned copper wire used as a common lead.
Butt Splice: A splice wherein two wires from opposite ends butt against each other, or against a stop, in the center of a splice.
Butyl Rubber: A synthetic rubber with good electrical insulating properties.
Byte: A sequence or group of 8 bits. A byte can represent one character or digit.

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