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Term Description CA Conditional Access. A system to control subscriber access to services, programs and events e.g. Nagra, Viaccess, Irdeto, SECA. Cable CABLE is short for cable TV (CATV) network. Internet access is provided on the same cable as regular cable TV and is offered by cable companies. The subscriber requires a cable modem. Cable provides potential speeds up to 10Mbps, but the number of users on the system affects the overall access speed. Cable modem A modem that sends and receives data through a coaxial cable television network instead of the telephone lines. A type of modem that connects a computer to the cable TV (CATV) network, which in turn connects to the Internet. Once connected, cable modem users have a continuous connection to the Internet. Cable modems feature asymmetric transfer rates: around 36 Mbps downstream and from 200 Kbps to 2 Mbps upstream. It is a modem in the true sense of the word that modulates and demodulates signals and delivers Internet data to the desktop at blazing speeds. It simply uses the increased bandwidth of the TV cable instead of an ordinary phone line. Cache Pronounced cash, a special high-speed storage/memory mechanism. It can be either a reserved section of main memory or an independent high-speed storage device. Two types of caching are commonly used in personal computers: memory caching and disk caching. CAM Acronym for Content Addressable Memory. It finds the address of specified data.   CAP Carrierless Amplitude/Phase modulation. A two-dimensional passband line code derived from QAM.   Carrier A long distance company which primarily uses its own transmission facilities, as opposed to resellers which lease or buy most or all transmission facilities from carriers. Many people refer to any type of long distance company, whether it has its own network or not, as a carrier, so the term is not as restrictive as it used to be.   Carrier Access Code (CAC) The sequence an end user dials to obtain access to the switched services of a carrier. Carrier Access Codes for Feature Group D are composed of five digits, in the form 10XXX, where XXX is the Carrier Identification Code.   Carrier Common Line Charge (CCLC) A per minute charge paid by long distance companies to local phone companies for the use of local public switched networks at either or both ends of a long distance call. This charge goes to pay part of the cost of telephone poles, wires, etc.   Carrier Identification Code (CIC) The three-digit number that uniquely identifies a carrier. The Carrier Identification Code is indicated by XXX in the Carrier Access Code. The same code applies to an individual carrier throughout the area served by the North American numbering plan.   Carrier System A system for providing several communications channels over a single path.   Carry-chain See carry logic   Carry-logic An FPGA architectural feature for efficient, high speed arithmetic functions.   Cartridge May refer to ROM cartridge, font cartridge, emulation cartridge, toner cartridge, toner/developer cartridge or print cartridge.   CBC Cipher Block Chaining   CCK Complimentary Code Keying   CD Compact Disc   CDMA Code Division Multiple Access. A spread-spectrum digital cellular radio system that uses different codes to permit and distinguish users operating simultaneously on the same frequency. This technique is used to increase channel capacity. Typically each user is given a different pseudo-random spreading code. To communicate with a particular user, the sender must select the code assigned to that user.   CEBus Consumer Electronics Bus. A communications standard for in home networks developed by the Electronics Industry Association (EIA) and the Consumer Electronics Manufacturers Association. CEBus is a standard for a communication network for consumer products in the home. CEBus is an open architecture which explains how to make products communicate through; Power line wires, Low voltage twisted pairs, Coax, Infrared, RF, and Fiber optics. The CEBus based products consist of two fundamental components - a transceiver and a micro controller. The transceiver implements spread spectrum technology and the controller runs the protocol. Data packets are transmitted by the transceiver at about 10 Kilobits per second (Kbps), using spread spectrum technology. The CEBus protocol uses a peer-to-peer communications model so that any node on the network has access to the media at any time.   Cellular A wireless communications network architecture which employs "cells" or modular coverage areas, typically serviced by a "cell site or base station" and usually provides hand-off capability between cells for roaming devices.   Centronics Interface This 36-pin connection was designed by Centronics Corporation and has become the preferred way to attach most printers to a PC parallel data port.   CFB Cipher Feedback   Character Attributes A misnomer for typestyle, commonly used to refer to bold, italic, underline and other typestyle qualifiers used with a typeface.   Charged Roller A roller in a laser printer which imparts an electrostatic charge to another surface. Charged rollers are used in some small printers in place of corotrons to reduce ozone emissions.   CHI Concentration Highway Interface, a TDM scheme defined by Lucent.   Chip (Chipping Code) A term in spread spectrum, referring to the time it takes to transmit a bit or single symbol of a P.N. code (a single element of the spreading code).   ChipScope ILA Debugging tool that allows designers to see real-time signals within an FPGA through hardware functions and software programs.   Chrominance Portion of a video signal carrying color information.   Ciphertext The disguised message   Circuit Switched Circuit switched is a switching system in which a dedicated physical circuit path must exist between sender and receiver for the duration of the "call." Used in the phone company network, circuit switching often is contrasted with contention and token passing as a channel-access method, and with message switching and packet switching as a switching technique.   Circuit Switching A communications technology where a dedicated communications path is established between two stations. The path consists of dedicated channels on each physical link between the stations. The process of establishing these dedicated paths is referred to as signaling.   CISC Pronounced sisk, and stands for Complex Instruction Set Computer. Most personal computers, use a CISC architecture, in which the CPU supports as many as two hundred instructions. An alternative architecture, used by many workstations and also some personal computers, is RISC (reduced instruction set computer), which supports fewer instructions.   CLB Acronym for Configurable Logic Block. Xilinx FPGA architecture used to implement logic functions.   CLEC Competitive Local Exchange Carrier (alternative local phone or data company). A company that builds and operates communication networks in metropolitan areas and provides its customers with an alternative to the local telephone company.   Clock enable Clock enable is a feature for a flip flop (memory element - storage device) that allows efficient use of clocks.   Clock Skew See skew   Clock Speed Also called clock rate, the speed at which a microprocessor executes instructions. Every computer contains an internal clock that regulates the rate at which instructions are executed and synchronizes all the various computer components. The CPU requires a fixed number of clock ticks (or clock cycles) to execute each instruction. The faster the clock, the more instructions the CPU can execute per second. The frequency at which a design or system may run.   Clock-to-out (Tco) Timing parameter that specifies the time it takes for a signal to appear on the output of a flip flop or I/O after the clock.   CMTS Cable Modem Termination System   CMYK The Cyan Magenta Yellow Black model for standards in color ink jet printing. These are the four basic process colors used in conventional color printing. By overlaying or dithering combinations of these four inks in different proportions, a vast range of colors can be created.   CO Central Office. This refers to the local telephone exchange or the local switching center of a local telephone company office which connects to all local loops in a given area and where circuit switching of customer lines occurs. It is the local telephone company switching system, where Telephone Exchange Service customer station loops are terminated for purposes of interconnection to each other and to trunks. The name is historically derived from the point where operators in an office were the switching function, connecting and disconnecting calls manually.   CO Central Office - telephone company equipment to terminate and interconnect customer lines.   Coax, Coaxial Cable A concentric, two-conductor cable in which one conductor surrounds the other, separated by an insulator.   Coaxial Cables A solid center conductor is surrounded by an insulating spacer which in turn is surrounded by a tubular outer conductor (usually a braid, foil or both). The entire assembly is then covered with an insulating and protective outer layer. Coaxial cables have a wide bandwidth and are capable of carrying many data, voice, and video conversations simultaneously. A type of cable used to transport high frequency signals, e.g. from the LNB to the satellite receiver.   Code A code refers to a digital bit stream with noise-like characteristics. In spread spectrum technique, the term code refers to the pseudo-random code used to control the modulation technique used to spread the carrier.   Code Rate This is equal to the number of information symbols percode word divided by the total number of symbols per code word.   Code Word A block of n symbols.   CODEC COder­DECoder. Coder and Decoder function that converts analog signal into digital pulse-coded-modulation format for transmission through the digital public switched network. These devices also provide the pre- and post-filtering for optimal performance over varying loop conditions. An assembly comprising an encoder and a decoder in the same unit. In video, refers to compression and decompression.   Coding Gain The amount of power saved by using Reed-Solomon prior to transmitting.   Coefficients A constant that is multiplied by a variable is known as a coefficient or a scaling variable. It is commonly used in DSP applications.   Collisions In network systems, when two nodes transmit simultaneously, causing destruction of a data packet's information.   Common Interface Describes a hard and software architecture for Conditional Access Systems whereby the generic "host" Set-top Box is not dedicated to one particular encryption system. Consumers use detachable modules, which allow them to receive encrypted services they pay subscription fee for. The interface between host Set-top Box and module is standardized (PCMCIA-Interface) so that the same Set-top Box can be used to handle a variety of encryption systems.   Component video The video signal separated into different pieces.See RGB, S-Video.   Composite Black The creation of black from cyan, magenta and yellow inks. Mixing inks is not a perfect operation, and composite black is often muddy. This is why the CMYK model is used in professional printing. See also True Black.   Composite video All components (brightness, color, synchronization, etc.) combined into one signal. See component video. Compression In RF amplification, an amplifier is said to be "in compression" (distorting) when the output is no longer a linear representation of the input signal, typically at the operational limits of the amplifier.   Compression ratio The size of the original image divided by the size of the compressed image, measuring the degree to which a compression routine can reduce the size of a file.   Conditional Access (CA) A system for scrambling and encryption signals in order to deny access to programs for those viewers who have not paid subscription fees for these programs. (E.g. Videoguard, Eurocrypt).   Configurable Logic Block See CLB   Configuration It is the process of loading design-specific bitstreams into one or more FPGA devices to define the functional operation of the logical blocks, their interconnections, and the chip I/O.   Configuration Mode Control SpartanXL devices have three configuration modes: Slave Serial, Master Serial and Express Mode. These modes are selected by the M1 and M0 pins on the device. In addition, the devices can be configured through boundary scan logic.   Connectivity The ability of a device to communicate with other devices through a data communications medium.   Consumer devices Consumer electronic devices such as digital TV, PCs, gaming consoles, web phones, set-top boxes, printers, scanners, etc.   Contour Font An alternative term for an outline font.   Control Unit The part of the processor which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.   Controller Normally an abbreviation of printer controller, the dedicated computer in a printer which creates the image to be printed.   Convolution Sum This is the summation of the products of the impulse response and the input sequence.   Core (IP) See intellectual property   CORE Generator Xilinx software tool that is used to select the appropriate IP core and customize it.   Corotron A wire in the printer mechanism which carries a very high voltage to generate an electrostatic charge on a nearby surface, such as photoreceptor or sheet of paper. There are several corotrons in most printers. The high voltage in corotrons ionizes the air surrounding the corotron and generates ozone gas as a by-product.   Correlator The receiver component that demodulates a spread spectrum signal. It is used to measure the similarity of two signals. It is also referred to as a "de-spreader" in direct sequence systems.   CPE Customer Premises Equipment. Telecommunications equipment that is located at the subscribers' home or business and that could potentially belong to the customer rather than the network operator.   CPLD Complex Programmable Logic Device. Non-volatile programmable device that is based on programmable AND-OR structure.   CPU Central Processing Unit. It is the main processing element of a switch or microprocessor and thus is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system. Two typical components of a CPU are: ALU and the control unit.   CRC Cyclic Redundancy Check. CRC is a technique to detect and correct errors during data transmission.   Critical path Logic path that limits the performance of a design.   Cross-probing Ability of different software tools or applications to talk to each other.   CrossTalk The unwanted energy (speech or tone) transferred from one circuit to another circuit.   CRT Cathode Ray Tube   Cryptanalysis The art of breaking cryptosystems, and seeing through the disguise even when you are not supposed to be able to.   Cryptographic Encryption   Cryptography Originally, the science and technology of keeping information secret from unauthorized parties by using a code or a cipher. Today, cryptography can be used for many applications that do not involve confidentiality including digital signature, data integrity and authentication.   Cryptology The study of both cryptography and cryptanalysis.   Cryptosystem or cipher system A method of disguising messages so that only certain people can see through the disguise.   CS Acronym for Chip Scale Package. It is a leadless, surface mount, low profile package.   CSMA Carrier-Sense Multiple Access   CSMA/CA Carrier Sense Multiple Access / Collision Avoidance   CSMA/CD Carrier Sense Multiple Access/ Collision Detect protocol. With CSMA/CD two or more stations share a common transmission medium. To transmit a frame, a station must wait for an idle period on the medium when no other station is transmitting. It then transmits the frame by broadcasting it over the medium such that it is "heard" by all the other stations on the network. If another device tries to send data at the same time, a "collision" is said to occur. The transmitting station then intentionally transmits a "jam sequence" to ensure all stations are notified the frame transmission failed due to a collision. The station then remains silent for a random period of time before attempting to transmit again. This process is repeated until the frame is eventually transmitted successfully. CSMA/CD access is used by Ethernet (IEEE 802.3), HomePNA and wireless LANs (IEEE 802.11).   CTT Acronym for Center Tap Terminated. I/O Standard for memory bus applications.   Customer Access Line Charge (CALC) The FCC-imposed monthly surcharge added to all local lines to recover a portion of the cost of telephone poles, wires, etc., from end users. Before deregulation, a large part of these costs were financed by long distance users in the form of higher charges.   Cycle Time A measurement of how quickly two back-to-back accesses of a memory chip can be made.     A  B  C  D E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z