B b Bit. B Byte. B1 Level of security established by the Department of Defense. B8ZS Bipolar 8 Zero Substitution. back haul 1. Routing a call through a network in an indirect manner because it is less expensive to do so. 2. Link between a central office and a main microwave or multiplex station, or between a ground satellite station, or submarine cable terminal and switching center. back-end network A local area network that connects computers and I/O subsystems to shared storage devices. Backend networks can also be used during excessive data transmission across the network. back-end processes The functions performed by a data base server in response to directions from an application running on an end-user PC. back-off time The workstation transmission delay period immediately following a network collision in a CSMA/CD environment. backbone network The high-density portion of a network that connects primary nodes. backfile conversion The process of scanning in, indexing, and storing a large backlog of paper or microform documents in preparation of an imaging system. background ink A reflective ink used to print the parts of a document that are not meant to be picked up by a scanner or optical character reader. backplane Connector blocks and special wiring on rear of shelf (printed circuit board modules normally mount on front of the backplane). BAL Basic Assembler Language (Unisys). balun BALanced/UNbalanced. Device frequently used to connect any 3270-type terminal, that requires a coaxial cable (unbalanced), in order to function on twisted-pair cabling (balanced). BAM Basic Access Method. band 1. A range of frequencies between upper and lower limits. 2. In relation to metered services (e.g., WATS, Advanced WATS, etc.), the specific geographical area that the customer is entitled to call. band buffer Temporary storage where a band of video output (32 scan lines) is held before being fed to a laser-based printer. bandpass The portion of a band, expressed in frequency differences (bandwidth), in which the signal lost (attenuation) of any frequency when compared to the strength of a reference frequency is less than the value specified in the measurement. bandsplit The technique of subdividing a channel (band) into subchannels. bandwidth The frequencies assigned to a channel, measured by computing the difference, expressed in the number of cycles per second, between the nominal upper and lower limiting frequencies of a band. The term is used less formally to represent the maximum number of information units (e.g., bits, characters) capable of traversing a communications path in one second. Bandwidth on Demand Interoperability Group An industry trade group formed to establish bandwidth-on-demand services standards. bandwidth-limited operation The condition in a fiber-optic link when bandwidth, rather than received optical power, limits performance. bar code A system of portraying data in a series of machine-readable lines of varying widths. barge in The interruption of an already established connection. See also executive override. barium ferrite A type of magnetic particle used in some recording media including floptical diskettes. base station A fixed land station that provides telephone service for mobile stations, i.e., telephones. baseband The total frequency band occupied by the aggregate of all voice and data signals used to modulate a radio carrier. In a baseband LAN, the entire capacity of the cable transmits one high speed channel which all attached devices share. baseband signaling The unmodulated transmission of signals at their original frequencies. BASIC Beginner's All-Purpose Symbolic Instruction Code. basic rate interference (BRI) In ISDN, two bearer B-channels at 64K bps and a data D-channel at 16K bps. Basic Telecommunications Access Method BTAM; an access method that permits read/write communications with remote devices. batch A group of data items processed as one unit. batch processing See processing, batch. battery backup A battery that provides power in the event of a AC power failure. baud A unit that indicates transmission speed. Baud typically represents bits per second. Baudot code See code, Baudot. bay See rack. BBS See Bulletin board system. BCC See block check character. BCD See binary coded decimal. BCL Burroughs Common Language (Unisys). BCML Burroughs Current Mode Logic (Unisys). BCP 1. Basic Control Program (Unisys). 2. Bisynchronous Communication Processor (Hewlett-Packard). BCPL Basic Combined Programming Language. BDAM Basic Direct Access Method. BDLC Burroughs Data Link Control (Unisys). beamsplitter An optical device that splits a beam of light into two or more beams. Bell 103 AT&T's standard for 300-bps, asynchronous, full-duplex modems with originate and answer capability. Bell 113 AT&T's standard for modems that provides originate or answer capability. Bell 201B AT&T's standard for 2400-bps, synchronous, full-duplex modems used over public telephone networks or leased lines. Bell 201C AT&T's standard designed for half-duplex modems used over public telephone networks. Bell 202 AT&T's standard for 1800-bps, asynchronous, four-wire, full-duplex modems and 1200-bps, two-wire, half-duplex modems. Bell 208A AT&T's standard for 4800-bps, synchronous modem transmission over leased lines. Bell 208B AT&T's standard for 4800-bps, synchronous modem transmission over public telephone networks. Bell 209 AT&T's standard for 9600-bps, synchronous modems over four-wire leased lines. Bell 212 AT&T's standard for 300- and 1200-bps, asynchronous, full-duplex modems. Bell Operating Company (BOC) Any of the 22 operating companies of AT&T resulting from the divestiture. bell-off enable An attendant console feature allowing the bell ringer to be turned off; incoming calls are identified by flashing LEDs only. Bellcore Bell Communications Research. Organization formed at divestiture to provide centralized services and establish standards for the seven Regional Bell Holding Companies (RBHCs) and their operating company subsidiaries. benchmark (BM) A standardized task given to versions of the same device to evaluate their performances against one another. BER See bit error rate. Berkeley Extensions Extension to UNIX, developed by the University of California at Berkeley. These extensions include networking and larger file names. Berkeley Software Distribution Sockets (BSD) Layer five of the OSI model. Bernoulli box A storage disk system that uses the principles of fluid dynamics (discovered by 18th century Swiss scientist Daniel Bernoulli). When the disk rotates at great speed, it creates a cushion of air, keeping the read/write head at the perfect close distance from the disk's surface. Capacity depends on the cartridge capacity, which range from 10 to 90 megabytes. BERT See bit error rate test/tester. binary A number system that uses only two characters (0and 1). binary code Actual representation of a quantity in a base-2 number system. binary exponential backoff A LAN algorithm used to reschedule transmissions after a collision. binary phase-shift keying See phase shift keying. binary synchronous communications (BSC, bisync) The synchronized transmission of binary-coded data. binary-coded decimal (BCD) A binary-coded notation in which each of the decimal digits is represented by a binary numeral. biometrics Collective term used to describe a set of network security procedures that identify individuals according to biological characteristics such as fingerprint, handprint, voice quality, pattern of capillary blood vessels in the retina of the eye, or habitual typing rhythms. BIOP Buffer Input/Output Processor. BIOS Basic Input/Output System. bipolar The predominant signalling method used for digital transmission services, including DDS and T1. See also alternate mark inversion. bipolar pulse violation (BPV) A bipolar pulse with the same polarity as the preceding pulse. bipolar violation Presence of two consecutive "one" bits of the same polarity on the T carrier line. BIS Business Information System. bis Appended to some ITU-TSS network interface standards. Also used to identify the second version of a specific ITU-TSS standard. BISAM Basic Indexed Sequential Access Method. BISDN Broadband ISDN. See ISDN. bisync See binary synchronous communications. bit Contraction of binary digit, the smallest unit of information in a binary system. A bit represents the choice between a mark or space (one or zero) condition. bit depth Number of colors or levels of gray that can be displayed at one time; controlled by the amount of memory in the computer's graphics controller card. bit duration Used to measure delay times, usually in high speed communications, it's the time it takes for one bit to pass a point on the transmission medium. bit error rate (BER) The number of erroneous bits divided by the total number of bits over a stipulated period of time. The BER is usually expressed as a number and a power of 10 (e.g., 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 in 10 or 2.5 x 10). bit error rate test/tester (BERT) A method or device used to measure the quality of the bit transmission, the pattern of bit transmission, and the number of bit errors received. The figures obtained are used to compute the BER. bit mapped display A technique in which images are produced by coupling each pixel (picture element or dot) in a display with a particular bit in memory. The result produces displays of superior resolution. bit rate The speed at which bits are transmitted, usually expressed in bits per second (bps). See also baud. bit stuffing Insertion of an occasional dummy bit into a binary stream so that the mean data rate is slightly less than the bit signaling rate of the channel. The position of the stuffed bits must be signaled on a supplementary channel. Also called pulse stuffing. bitmap Representation of characters or graphics by individual pixels, or points of light, dark or color, arranged in row (horizontal) and column (vertical) order. Each pixel is represented by either one bit (simple black & white) or up to 32 bits (fancy high definition color). bitmap display In a bitmap display, a screen image is generated through a 1:1 correspondence between bits in memory and pixels on the screen. bitmapped graphics Images which are created with sets of pixels, or dots. Also called raster graphics. Contrast with vector graphics. BITNET An alternative public network that has steadily become more tightly connected to the Internet. bits per second (bps) Rate at which data transmission is measured. BLERT See block error rate test/tester. BLF See see busy lamp field. BLOBs (Binary large objects) Massive image files to be moved across LANs. block 1. A sequential, generally delimited collection of related data items. 2. A segment that represents a portion of a message. block check character(s) See block redundancy check. block error rate The number of blocks received with errors compared to those received correctly. block error rate test/tester (BLERT) A method or device used to measure the quality of the block transmission, the pattern of block transmission, and the number of block errors received. The figures obtained are used to compute the block error rate. block length The total number of records, words, or characters contained in one block. block redundancy check (BRC) Information added to a transmitted block to verify accuracy of data before it is accepted. Block check data is developed by the sender as a predefined function of information in the block; the receiver performs the same function on received data and compares the calculated and received block checks. The block is accepted only if the comparison is exact. Also called block check character(s). block-chaining Linking blocks of message data in main or secondary storage by way of pointer arrangements to provide for queuing and for flexibility of memory use. blocked call A call that cannot be completed because all lines to the CO are in use or all connecting paths through the PBX switch are in use. blocking The inability of a telecommunications system to establish a connection because paths are unavailable. BLT Block Line Transfer. BNA Burroughs Network Architecture (Unisys). board A circuit card that can be altered with the addition or deletion of external wiring. BOBs See breakout boxes. BOC See Bell Operating Company. BONDING (Bandwidth on Demand Interoperability Grou An industry trade group formed to establish bandwidth-on-demand services standards. BOOTP BOOTstrap protocol allows a workstation to obtain its IP address dynamically from a host or file server. BOSS Basic Operating System (Basic Four). BPAM Basic Partitioned Access Method (IBM). bpi Bits per inch. BPL Binary Program Loader. bps Bits per second; rate at which data transmission is measured. BPS Basic Programming Support (IBM). BPSS Basic packet-switching service. BPV See bipolar pulse violation. BRC See block redundancy check. breakout box Device designed to test cable. breakout panel As part of a larger device, a breakout box is mounted as a component. bridge A PC, equipped with an adapter and bridge software, that connects networks using the same protocols. See also gateway. bridge lifter A device that isolates bridged telephone pairs, often by using relays or saturable inductors. bridged call A feature allowing a station user to join a conversation by entering the proper command code to become an extension of another line. broadband A data-transmission technique that allows multiple signals to share the same transmission bandwidth. broadband communications Communications that require high levels of transmission capacity or bandwidth. broadband network A network capable of transporting voice, data services and interactive full-motion video. A network capable of transmitting 1.5 million or more pieces information per second. broadband PCs A connection-oriented and connectionless digital wireless communications services that will utilize channels in the 1.8- to 2.2GHz band to be auctioned by the FCC. broadcast 1. Dissemination of information to a number of stations simultaneously. 2. (In LAN technology) a transmission method used in bus topology networks that sends all messages to all stations even though the messages are addressed to specific stations. broadcasting-satellite space station A space station in the broadcasting-satellite service on an earth satellite. broker call A feature that allows an extension user, while engaged on one call, to place the first call on hold, originate a new call, and then alternate between the calls, carrying a private conversation with either party. See also consultation hold. brokerage -- hot line Establishes connection to predetermined stations or attendant consoles within the PBX system. brouter A device that functions as both a bridge and a router.See also bridge and router. browser The program that allows a user to locate and view documents on the Web. BSAM Basic Sequential Access Method. BSC See binary synchronous communications. BSD Berkeley Software Distribution Sockets; Layer Five of the OSI model. BSFT Byte Stream File Transfer; defines the exchange of unstructured data among X/Open systems. BSP Burroughs Scientific Processor (Unisys). BTAM See basic telecommunications access method. BTAs Basic trading areas. bubble One technique for recording data on optical discs. A laser strikes the non-image areas of the recording medium, causing bubbles to form and leaving the image area clear to reflect the reading laser's light. bubble jet A printer technology in which a miniature electric heater is imbedded above each of the print head's group of nozzles. Electric current flows to the heater element to create a bubble. The bubble creates a disturbance in the ink chamber and forms a droplet. Thousands of droplets form an image. bubble memory A nonvolatile storage technique that uses pulse of magnetism to create isolated islands or bubbles of data. buffer A data storage medium used to compensate for a difference in the rate of data flow or time of occurrence of events when transmitting data from one device to another. bug A problem in software or hardware, be it a mistake or a malfunction. bulk encryption The process whereby two or more channels of a telecommunications system are encrypted by one crypto-equipment. bulletin board Computer systems that function as centralized information sources and message switching systems for a particular group of users. bulletin board system (BBS) An electronic bulletin board that function as centralized information sources and message switching systems for a particular group of users. Callers can call the BBS, attach, access information and download directly to their system. bundled A pricing strategy combining several services or products under one price. bundled rates Rates in which the various rate elements that comprise the service are consolidated, thereby making them indistinguishable. burst In data communications, a sequence of signals counted as one unit in accordance with some specific criterion or measure. burst mode The transmission of bulk data in large, continuous blocks over a channel that is used exclusively for the extent of the transmission. burst traffic Data is transmitted in bursts, instead of continuously. bus A circuit that interconnects multiple locations or devices over a single continuous path. bus network A network topology in which all terminals are attached to a transmission medium serving as a bus. bus topology A network design in which all workstations are connected to a common communications channel comprised of fiber-optic, coaxial, or twisted-pair cabling. busy A station or trunk line which is in use. busy hour The period during which a system carries the most traffic -- typically, the busy hour of the busy day of the work week. Peaks caused by holidays or special events are not considered. The busy hour is usually one of the factors determining the type of system configuration. busy hour calls The number of calls a system can handle within the busy hour. busy lamp field (BLF) An attendant console peripheral that enables the attendant to track the status of all stations from a lighted panel or series of lamps. busy override or intrude See executive override. busy trunk release A feature that allows the attendant or repair technician to release a trunk that has been busied out from the console. busy verification The ability to check the busy/idle status of lines or trunks by using the busy lamp field. See also attendant busy override and/or executive override. bypass The automatic connection of specified extensions to trunks or CO lines during a system failure. bypass circuitry A group of devices that restore failed network links and equipment. byte A small group of bits, usually eight, that represent the smallest addressable unit in memory. See also ASCII and BSC. byte-oriented protocol A protocol technique using defined characters (bytes) from a code set for communications control. Compare with bit-oriented protocol. See also ASCII, BSC, and DDCMP.