| Term |
Definition |
| B8ZS |
A technique used to accommodate the ones density requirements of a public network T1 transmission facility. |
| Back Porch |
The portion of the video waveform between the trailing edge of the horizontal sync and the start of active video. |
| Backbone |
A segment of network that links several individual workgroup or department LANs together in a single building. Backbone can also refer to the high-speed communications links that connect Internet providers, large Internet sites, and networks. |
| Backbone System |
The transmission network that carries high speed transmission of telecommunications between regions. |
| Back-off |
The process whereby an attempt to perform a particular process is discontinued. The most likely reason for the suspension being that a problem with the process was detected. In a communications sense one example is the process whereby a transmitting station backs-off (and tires again later) when a signal disruption of some form occurs. |
| Backoff Delay |
The length of time that a station on a CSMA/CD (Ethernet) network must wait before attempting to retransmit a frame after detecting a collision. |
| Backward Channel |
A transmission channel, associated with but used in the opposite direction to, a specific information transfer channel, used to carry supervisory or error control data. |
| Balanced Error |
The description of a facility which has a distribution of errors such that the mean value can be considered zero. |
| Balanced Transmission |
A mode of signal transmission in which each conductor carries the signal of equal magnitude, but opposite polarity. A 5 volt signal for example, appears as a +2.5 Volts on one conductor and -2.5 Volts on the other. |
| Balanced Transmission Line |
A line having conductors with equal resistance per unit length and equal capacitance and inductance between each conductor and ground. Co-axial cable is easily configured as a balanced transmission system by the use of "resistance to ground" terminators. |
| Balun |
An impedance matching transformer that converts the impedance of one interface to the impedance of another interface. Sometimes used to adapt 150 ohm shielded twisted pair (STP) cabling for use with 100 ohm Ethernet systems. The term is derived from "balanced / unbalanced". May also be called a "media filter". |
| Band |
The range of available frequencies defined by a higher and lower limit. |
| Band Splitter |
A Multiplexer designed to split the available frequency band into several independent channels suitable for data transmission. |
| Bandpass Filter |
A device which will only "pass" of conduct frequencies within a defined range referred to as the frequency band. |
| Bandwidth |
The bandwidth of a transmitted communications signal is a measure of the range of frequencies the signal occupies. All transmitted signals, whether digital or analog, have a certain bandwidth. Generally speaking, bandwidth is directly proportional to the amount of data transmitted or received per unit time. |
| Bare board |
A printed circuit board (PCB) that does not have any components on it. |
| Barrel Connector |
A connector which is used to "straight line" connect two to lengths of co-axial cable. Note: In ethernet installations where the number of connection nodes (for devices) is limited a barrel connector normally counts as a node. |
| Base Station |
A radio transceiver that is located near the center of each cell in a cellular telephone network and which communicates with all of the active cellular telephones in the cell and provides them with a connection to the switched telephone network. |
| Baseband |
A transmission method in which the entire bandwidth of the transmission medium is used to transmit a single digital signal. The signal is driven directly onto the transmission medium without modulation of any kind. Baseband is simpler, cheaper and less sophisticated than Broadband. All Ethernet media types are baseband except for 10Broad36 which is broadband. |
| Baseband Signal |
A signal that is not modulated onto a carrier. In a cellular telephone, all of the analog and digital signals except the radio frequency portion of the telephone. |
| Baud |
The number of changes in signal per second. A given baud rate does not necessarily transmit an equal number of bits/sec. For example, a signal with four voltage levels may be used to transfer two bits of information for every baud. |
| Baud Rate |
The amount of information conveyed per second. The baud rate is only equivalent to the bit rate when 1 bit represents one bit of information. |
| Baudot |
A encodation method in which five bits are used to represent "real world" characters. |
| B-CDMA |
Broadband code division multiple access (wireless communication technology developed by InterDigital Communications Corp.) |
| BCI |
BroadCast Interference |
| B-DCS |
Broadband digital cross-connect |
| Beam Splitter |
A device for splitting an optical transmission beam into two or more separate beams. |
| BECN (Backward Explicit Congestion Notification) |
A bit set by a Frame Relay network to notify an interface device (DTE) that congestion avoidance procedures should be initiated by the sending device. |
| Bend Loss |
A form of increased attenuation in an optical fiber caused by an excessively small bend radius. The attenuation may be permanent if microfractures caused by the bend continue to affect transmission of the light signal. |
| Bend Radius |
Radius of curvature that a fiber optic or metallic cable can bend before the risk of breakage or increased attenuation occurs. |
| BER |
Bit Error Rate - A ratio of the number of digital errors re-ceived in a specified period to the total number of bits received in the same period. Usually expressed as a negative ex-ponent, i.e.; 10-6 ; means one bit error in 106 bits of transmission, or one in a million. |
| BGA |
Ball Grid Array. |
| Bias Distortion |
A type of distortion in transmission systems which causes mark and space pulses to be lengthened or shortened. |
| BIB |
British Interactive Broadcasting. |
| B-ICI |
Broadband Inter-Carrier Interface. |
| BICMOS |
Bipolar Complementary Metal Oxide Semiconductor. |
| BIFET |
BIpolar Field-Effect Transistor. |
| BIMOS |
Bipolar Metal Oxide Semiconductor. |
| Binary Code |
A pattern of logical zeros and ones which is used to represent "real world" information. |
| Binary Phase Shift Keying (BPSK) |
A phase shift modulation technique. |
| Bipolar Waveform |
A transmission method which uses opposite polarity for successive mark (logical one) pulses and a neutral signal state for the space (logical zero) pulses. |
| B-ISDN |
Broadband Integrated Services Digital Network - A standard for transmitting voice, video and data at the same time over fiber optic telephone lines. Broadband ISDN can support data rates of 1.5 million bits per second (bps), but it has not been widely implemented. |
| Bi-stable Optics |
Optical devices with two stable transmission states. |
| Bit |
Binary digit, the smallest piece of binary information, i.e. one of two possible states. |
| Bit Duration |
The time it takes ONE encoded bit to pass a specified point. |
| Bit Interleaving/Multiplexing |
A process used in time division multiplexing where individual bits from different lower speed channel sources are combined (one bit from one channel at a time) into one continuous higher speed bit stream. |
| Bit Oriented Protocols |
Data link control protocols which use specific bit patterns to transfer controlling information. Examples are SDLC (IBM) and HDLC (CCITT). Bit oriented protocols are normally used for synchronous transmission only. Bit oriented protocols are code transparent (work regardless of the character encodation method used) since no encoded characters are used in the control sequence. |
| Bit Rate |
The number of bits per second. |
| Bit Stream |
A continuous transfer of bits over some medium. |
| Bit stuffing |
A technique used to ensure that transmitted control information is not misinterpreted as data by the receiver during bit oriented transmission. Additional binary zeros are inserted at the transmitter after certain bit pattern transmission, such bits are then removed at the receiver. This technique may also be refereed to as zero bit insertion. |
| BJT |
Bipolar junction transistor. |
| Black body |
A body or material that absorbs 100% of the energy incident upon it. In equilibrium it will absorb 100% of the energy incident up on it, meaning it will not reflect it in the same form. |
| Black Burst |
Black burst is a composite video signal with a totally black picture. It is used to synchronize together video equipment so the video outputs are aligned. Black burst tells the video equipment the vertical sync, horizontal sync, and the chroma burst timing. |
| Black Level |
This level represents the darkest an image can get, defining what black is for a particular video system. If for some reason the video goes below this level, it is referred to as blacker-than-black. You could say that sync is blacker-than-black. |
| BLAM |
Binary Logarithmic Arbitration Method. |
| BLAST |
Blocked Asynchronous Transmission - A popular communications method which produces error free transmission of blocks of data. |
| Block |
A set of characters which are normally stored or transmitted as a group. |
| Blooming |
This is an effect, sometimes caused when video becomes whiter-than-white, in which a line that is supposed to be nice and thin becomes fat and fuzzy on the screen. |
| Blown Fiber |
A method for installing fiber in which fibers are through a vessel, for instance a tube. |
| Bluetooth |
Short range radio technology expanding wireless connectivity to personal and business mobile devices enabling users to connect their mobile phones, computers, printers, digital cameras and other electronic devices to one another without cables. |
| BNC |
A coaxial connector that uses a "bayonet" style turn and lock mating method. Used with RG-58 or smaller coaxial cable. Used with 10Base2 Ethernet thin coaxial cable. |
| Bond pad |
Square metallic pads on the die where the BALL BOND is attached. The bond pad is used to find acceptable eyepoints. |
| BootP |
A protocol which is used by a network node to determine the IP address of its Ethernet interfaces. |
| BORSCHT |
Acronym for the functions performed at the central office by the SLIC for digital voice-transmission. Battery, Over-voltage, Ringing, Supervision, Coding, Hybrid and Test. |
| BPI |
Bits Per Inch. |
| BPON |
Broadband passive optical network. |
| Bps |
Bits per second; unit of measurement for data transmission speed over a data communications line. |
| Breezeway |
That portion of the video waveform between the trailing edge of horizontal sync and the start of color burst. |
| Bridge |
A networking device that connects two LANs and, using their addresses as destinations, forwards or filters data packets between them. |
| Bridge Tap |
An undefined length of wire connected between the normal end points of a circuit which introduces an unwanted modification of the transmission path characteristics. |
| Broadband |
Wideband technology capable of supporting voice, video and data, possibly using multiple channels. |
| BSC (base station controller) |
Provides the control functions and physical links between the MSC and BTS in a GSM mobile wireless network. The BSC controls the interface between the SGSN and the BTS in a GPRS network. The BSC is a high-capacity telephony switch that provides handoff functions, cell configuration data, and controls radio frequency power levels in BTSs. The combined functions of the BSC and BTS are referred to as the BSS. |
| BSI |
British Standards Institution. |
| BSS (base station subsystem) |
Refers to the radio-related functions provided by the BTS and BSC in a GSM mobile wireless network. |
| BTS (base transceiver station). |
Land-based station in a GSM mobile wireless network that consists of transceivers and antennas, which handle the radio interface to a mobile station. One or more BTSs are controlled by a BSC. The combined functions of the BTS and BSC are referred to as the BSS. |
| BTSC |
A technique of implementing stereo audio for NTSC video. One FM subcarrier transmits a L+R signal, and an AM subcarrier transmits a L-R signal. |
| BTU |
British Thermal Units. |
| Buffer |
A temporary storage space used to hold data while decisions are made on its integrity etc. |
| Buffer Coating |
This is a material applied to the fiber in layers, usually measured in microns, which increases the diameter of the fiber and protects and enhances the fiber performance. |
| Building Integrated Timing Supply (BITS) |
A clock, or a clock with an adjunct in a building that supplies DS1 and/or com-posite clock timing reference to all other clocks in that building. |
| Bus |
A transmission path or channel. A bus is typically an electrical connection with one or more conductors, where all attached devices receive all transmissions at the same time. |
| Bus Hog |
A slang term describing a device connected to a transmission bus which, after gaining access to the transmission medium, transmits a large number of messages regardless of whether other devices are waiting. |
| Bus Topology |
The network structure whereby connection between devices is accomplished by connecting all devices to a single transmission medium (wire, fiber, etc.). |
| BW |
BandWidth. |
| Bypass |
In common carrier voice network (telephone company) terms the process where by portions of the carrier's service are by passed using customer owned and operated facilities. Microwave links between offices to interconnect telephone circuits before they are connected to telephone company transmission/reception points is an example. |
| Bypass Relay |
A relay which is used to bypass failed stations in a network. Of significant importance in a token passing ring network. |
| Byte |
A set of eight bits. May also be referred to as an octet.A more general term than character since computer and data communications devices often use 8 bit bytes which do not have any "real world" equivalent. |
| Byte Multiplexing |
A form of time division multiplexing in which a single byte from each attached device is sent down the transmission channel in successive time slots. |
| Byte Stuffing |
The process whereby "dummy" bytes are inserted into a transmission stream so that the net data transmission rate will be less than the actual channel data rate. The "dummy" bytes are identified by a single controlling bit within the byte. |
| Bytes/s |
Bytes Per Second |
