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| A is for ... | ||
|---|---|---|
| ACC | Analog Control Channel | FSK control channel used in AMPS and dual-mode (IS-54B) cellular. |
| ADA | High-level programming language developed by the U.S. Department of Defense along with the European Economic Community and many other organizations. It was designed for embedded applications and process control but is also used for logistics applications. Ada is a Pascal-based language that is very comprehensive. Ada was named after Augusta Ada Byron (1815- 1852), Countess of Lovelace and daughter of Lord Byron. She was a mathematician and colleague of Charles Babbage, who was developing his Analytical Engine. Some of her programming notes for the machine have survived, giving her the distinction of being the first documented programmer in the world. | |
| ADPCM | Adaptive Differential PCM | Advanced PCM technique that converts speech to 32 or 16 Kbits/sec. Instead of coding an absolute measurement at each sample point, it codes the difference between samples and can dynamically switch the coding scale to compensate for variations in amplitude and frequency. |
| ADSL | Asynchronous Digital Subscriber Line | Also known as Asymmetric Digital Subscriber Line, or Asymmetric Digital Subscriber Loop. One of four DSL technologies. ADSL is designed to deliver more bandwidth downstream (from the central office to the customer site) than upstream. Downstream rates range from 1.5 Mbps to 9 Mbps, while upstream bandwidth ranges from 16 kbps to 640 kbps. ADSL transmissions work at distances up to 18,000 feet over a single copper twisted pair. This kind of connection is useful with applications such as interactive TV and Video on Demand, because the data the server sends is much more than the data sent by the client. ADSL uses bandwidth that is not used by voice; therefore voice and data can be transmitted at the same time. See also HDSL, SDSL, and VDSL. |
| AFAIK | As Far As I Know | Usenet/Chat acronym/abbreviation |
| ALERT | Advanced Law Enforcement & Response Technology | Is a police package vehicle equipped with advanced communications systems which will provide access to multiple sources of traffic enforcement and investigation information. An integrated architectural system design allows the officer to use everything from hand-held computers with citation, accident, and DWI arrest report forms, to global positioning system for precise location information. |
| AM | Amplitude Modulation | Transmission technique that blends the data signal into a carrier by varying (modulating) the amplitude of the carrier. |
| AMPS | Advanced Mobile Phone Service | 1. Analog Mobile Phone System. Non-digital cellular mobile phones. 2. Advanced Mobile Phone Service (Motorola). |
| ANSI | American National Standards Institute | Membership organization founded in 1918 that coordinates the development of U.S. voluntary national standards in both the private and public sectors. It is the U.S. member body to ISO and IEC. Information technology standards pertain to programming languages, EDI, telecommunications and physical properties of diskettes, cartridges and magnetic tapes. |
| APCO | Association of Public safety Communications Officials | The Association of Public-Safety Communications Officials - International, Inc. - APCO International - is the world's oldest and largest not-for-profit professional organization dedicated to the enhancement of public safety communications. With more than 13,000 members around the world, APCO International exists to serve the people who manage, operate, maintain, and supply the communications systems used to safeguard the lives and property of citizens everywhere. |
| API | Application Program Interface | Language and message format used by a program to activate and interact with functions in another program or in the hardware. |
| Applet | Small application, such as a utility program. See also Java. | |
| ARDIS | Advanced National Radio Data Service | Joint venture of IBM and Motorola that provides wireless data transmission in the 800MHz FM band. It covers most U.S. metropolitan areas with over 1,000 base stations. |
| ARP | Address Resolution Protocol | TCP/IP protocol used to obtain a station's physical address from its logical IP address. ARP requests are broadcast onto the network. Reverse ARP, or RARP, is used by a diskless workstation to obtain its logical IP address. Responding to a RARP broadcast from the workstation, a RARP server sends back the IP address. |
| ARPANET | Advanced Research Projects Agency NETwork | Research network funded by DARPA (originally ARPA) and built by BBN, Inc., in 1969. It pioneered packet switching technology and was the original backbone and testbed for the now-gigantic Internet. In 1983, the military communications part of it was split off into MILNET. |
| ASCII | American Standard Code for Information Interchange | A code in which each alphanumeric character is represented as a number from 0 to 127, translated into a 7-bit binary code for the computer. ASCII is used by most microcomputers and printers, and because of this, text-only files can be transferred easily between different kinds of computers. ASCII code also includes characters to indicate backspace, carriage return, etc., but does not include accents and special letters not used in English. Extended ASCII has additional characters (128-255). |
| ASIC | Application Specific Integrated Circuit | A customized microchip which is designed for a specific application. |
| ASP | Association of Shareware Professionals | A trade association for shareware authors. Members submit shareware, which is tested and checked for viruses, then distributed on CDs. |
| ASP | Active Server Pages | Active Server Pages is a compile-free application environment for Microsoft's IIS Web Server. ASP scripts can be embedded in an HTML document and are parsed by IIS before being sent to the client web browser. Active Server Pages provide a method to create dynamic or database driven web pages with IIS. Active Server Pages have native support for both VBScript and Jscript and can also embed ActiveX server components. |
| AT command set | Series of machine instructions used to activate features on an intelligent modem. Developed by Hayes Microcomputer Products, Inc., and formally called the Hayes Standard AT Command Set, it is used entirely or partially by most every modem manufacturer. AT is a mnemonic code for ATtention, which is the prefix that initiates each command to the modem. | |
| ATA | American Trucking Associations | The mission of the American Trucking Associations, Inc. is to serve and represent the interests of the trucking industry with one united voice; to positively influence Federal and State governmental actions; to advance the trucking industry's image, efficiency, competitiveness, and profitability; to provide educational programs and industry research; to promote highway and driver safety; and to strive for a healthy business environment. |
| ATM | At The Moment | Usenet/Chat acronym/abbreviation |
| ATM | Asynchronous Transfer Mode | High-speed packet switching technique suitable for MANs and broadband ISDN transmission. It uses cell relay transmission. |
| ATM | Automatic Teller Machine | Special-purpose banking terminal that allows users to make deposits and withdrawals. It can be a stand-alone unit or online to a central computer system. ATMs are activated by inserting a magnetic card (cash card or credit card) in the machine that contains the user's identification number. |
| A/V | Audio/Video | Refers to multi-media applications or sources. |
| AVC | Analog Voice Channel | A channel on which a voice conversation occurs and on which brief digital messages may be sent from a base station to a mobile station or from a mobile station to a base station. |
| AVI | Audio Video Interlaced (or Interleaved) | AVI is a Microsoft multimedia file format, similar to MPEG and QuickTime, used by Video for Windows. In AVI, audio and video elements are interleaved (stored in alternate segments) in the file. |
| B is for ... | ||
| Baud | A unit of measure of transmission speed. Named after J.M.E. Baudot (1845-1903), French engineer. Originally baud was used for telegraph transmissions, and meant one Morse code dot per second. Baud is a measure of the number of signal-state changes per second; for example, voltage, phase or frequency changes. It is sometimes, but not usually, the same as the number of bits per second. | |
| BBS | Bulletin Board Systems | Computer system used as an information source and message system for a particular interest group. Users dial into the BBS, review and leave messages for other users as well as communicate to other users on the system at the same time. BBSs are used to distribute shareware and may provide access (doors) to other application programs. |
| BCR | Bar Code Reader | Bar Code Readers can be hand operated pen type wands, which are wiped over a 1-D bar code to scan it, or hand-held laser-scan readers for both 1-D and 2-D codes, or fixed laser scanners (as in supermarkets). Image processing can also be used from a camera captured bar code. |
| BCR-HS | BCR High Speed | High speed CCD Bar Code Reader for reading 2D codes. |
| BER | Bit Error Rate | E.g. a BER of 10-3 means, that one of 1000 bits was not correctly transmitted. |
| BFN | Bye For Now | Usenet/Chat acronym/abbreviation |
| BMP | BitMaP | Picture format related to Windows environment. |
| BNC | Bayonet N-type Connector | Widely used on test equipment and for Ethernet connections. |
| Browser | A software application that displays World Wide Web documents | |
| BSI | British Standards Institute | The British body that publishes the International standards agreed by ISO in Britain. This means that all the standsrds are given at least two different numbers. One by ISO, one by BSI and sometimes another by CCITT. |
| BTS | Base Transceiver Station | These are the aerials that are put up by the cell phone operator usually on large buildings or on tops of hills and mountains. When a call is placed, the phone using the signalling channel signals the base station that a call is to be made to a number, it then passes your information and the number to the switching station known as a MSC (Mobile Switching Centre) the cell phone "Exchange" where your subscription is checked, if your subscription is valid the MSC routes the call and sets it up. The MSC then signals the base station to open up an available call channel to your phone and the phone at the other end rings. The radio link to your phone is controlled by the BTS, it alters the power output of your phone and also decides to route your call via another BTS in a "hand over" if it has difficulty with your call i.e the phone is nearer another BTS so it will use less power. The BTS is linked to the MSC by means of a microwave link or in some cases fixed cable connection |
| BTW | By The Way | Usenet/Chat acronym/abbreviation |
| C is for ... | ||
| CAN | Controller Area Network | Is an ISO defined multi-master serial communications bus that was originally developed during the late 1980's for the automotive industry. Its basic design specification called for a high bit rate up to 1M baud, high immunity to electrical interference and an ability to detect any errors produced. |
| CCD | Charge Coupled Device | Electronic memory in which metal oxide semiconductors are arranged so the output, or charge, from one semiconductor is the input of the next semiconductor. CCDs can be charged by light or electricity. One use is for storing images in digital cameras, video cameras, and optical scanners. |
| CCIS | Common Channel Interoffice Signaling | Telephone communications technique that transmits voice and control signals over separate channels. Control signals are transmitted over a packet-switched digital network, providing faster connects and disconnects and allowing data, such as calling number, to be included. |
| CCITT | Commite' Consultatif Internationale de Telegraphique et Telephonique (also Consultative Committee on International Telegraphy and Telephony) | The CCITT, now known as the ITU-T (for Telecommunication Standardization Sector of the International Telecommunications Union), is the primary international body for fostering cooperative standards for telecommunications equipment and systems. It is located in Geneva, Switzerland. CCITT do not make standards as such but instead make recommendations which member organisations are expected to conform to. These recommendations are limited to the specific needs of the member organisations. Since users of networks are generally subject to legal restrictions enforced by PTT's the numbers of bodies adhering to these standards are quite high. Recommendations from CCITT are generally prefixed with X if they relate to protocols eg. X25 or V if they relate to hardware eg. V24. |
| CCFL | Cold Cathode Fluorescent Lamp | Miniature high voltage cold cathode (field emission) lamp used for backlighting LCD's. |
| CCS | Common Channel Signaling | Integral part of ISDN known as "Signaling System 7," which advances the CCIS method for transmitting control signals. It allows call forwarding, call waiting, etc., to be provided anywhere in the network. |
| CDMA | Code Division Multiple Access | A technique of multiplexing, also called spread spectrum, in which analog signals are converted into digital form for transmission. For each communication channel, the signals are encoded in a sequence known to the transmitter and the receiver for that channel. |
| CDPD | Cellular Digital Packet Data | Transmission of digital data over the cellular network. |
| CD-ROM | Compact Disk Read Only Memory | An optical disk that is physically the same as an audio CD, but contains computer data. Storage capacity is about 680 megabytes. CD-ROMs are interchangeable between different types of computers. |
| CELP | Code Excited Linear Prediction | A technique of voice coding that makes use of linear prediction filters excited by a stimulus looked up from a pre-stored table, based on its similarity to the residue from the LPC filter solution. |
| CEMA | Computer & Electronics Marketing Association | CEMA is dedicated to educating and assisting high-tech marketing professionals, offering presentations by top keynote speakers and providing the opportunity to share information, explore common industry issues, problems and solutions. |
| CERN | Conseil Europeen pour la Recherche Nucleaire (in english - European Organization for Nuclear Research ) | CERN - the European Laboratory for Particle Physics - is one of the world's largest scientific laboratories. Founded in 1954, their site straddles the French- Swiss border west of the city of Geneva. The Laboratory is financed by 19 European countries. More than 7000 scientists, from laboratories and universities all over the globe, work there to study the constituents of matter and the nature of fundamental forces. |
| CFV | Call For Voting | Usenet procedure calling for votes on setting up a new News group. |
| CGI | Common Gateway Interface | A way of interfacing computer programs with HTTP or WWW servers, so that a server can offer interactive sites instead of just static text and images. |
| CLASS | Custom Local Area Signaling Services | A collection of services offered to local area residential and business customers on a pre-subscribed basis. These features support both local and interoffice applications where SS7 is deployed. CLASS features include: Calling Number Delivery, Calling Number Blocking, Customer Originated Trace, Automatic Recall, Automatic Callback, Selective Call Forwarding, Selective Call Waiting, Selective Call Rejection, Selective Call Acceptance, and VIP Alert. |
| CLI | Command Line Interface | An interface that allows the user to interact with the operating system by entering commands and optional arguments as in DOS and UNIX operating systems. See also GUI. |
| CLNP | ConnectionLess Network Protocol | The OSI protocol for OSI Connectionless Network Service. CLNP is the OSI equivalent to the Internet Protocol (IP), and has been called ISO IP. |
| CORBA | Common Object Request Broker Architecture | A program that helps transfer messages to and from objects between various platforms in a distributed environment. |
| COTS | Commercial Off The Shelf | Term often seen in military and government contracts meaning that standard equipment should be used and not something designed and built specially for the specific project. |
| CPU | Central Processing Unit | The CPU controls the operation of a computer. Units within the CPU perform arithmetic and logical operations and decode and execute instructions. In microcomputers, the entire CPU is on a single chip. |
| Cracker | A person who breaks into computer systems, using them without authorization, either maliciously or to just to show off. | |
| Crapplet | A badly written or profoundly useless Java applet. | |
| CRC | Cyclic Redundancy Coding (or Check) | A number derived from a block of data, and stored or transmitted with the data in order to detect any errors in transmission. It is similar to a checksum, but more complicated. A cyclic redundancy check is often calculated by adding words or bytes of the data. The receiving computer recalculates the CRC from the data received and compares it to the value originally transmitted; if the values are not the same, it indicates a transmission error. The CRC is called redundant because it adds no significant information to the transmission itself. |
| CRT | Cathode Ray Tube | Vacuum tube used as a display screen in a video terminal or TV. The term often refers to the entire terminal. |
| CSA | Canadian Standards Association | Agency within Canada that certifies products that conform to Canadian national safety standards. |
| CS-CDPD | Circuit Switched CDPD | Provides a mobile data communications system that uses landline and cellular telephone circuits, and modem banks, and interworks with the CDPD network. |
| CSMA-CD | Carrier Sense Multiple Access Collision Detection | Media-access mechanism wherein devices ready to transmit data first check the channel for a carrier. If no carrier is sensed for a specific period of time, a device can transmit. If two devices transmit at once, a collision occurs and is detected by all colliding devices. This collision subsequently delays retransmissions from those devices for some random length of time. CSMA/CD access is used by Ethernet and IEEE 802.3. |
| CTI | Computer Telephone Integration | Enabling computers to know about and control telephony functions such as making and receiving voice, fax, and data calls, telephone directory services, and caller identification. The integration of telephone and computer systems is a major development in the evolution of the automated office. |
| CTIA | Cellular Telecommunications Industry Association | |
| D is for ... | ||
| D-AMPS | Digital AMPS | Digital AMPS Cellular service using TDMA (Time Division Multiple Access) and the IS-136 specification. |
| DARPA | Defense Advanced Research Projects Agency | The central research and development organization for the Department of Defense (DoD). It manages and directs selected basic and applied research and development projects for DoD, and pursues research and technology where risk and payoff are both very high and where success may provide dramatic advances for traditional military roles and missions and dual-use applications. |
| DCCH | Digital Control CHannel | 48 kbits/second pi/4 DQPSK channel. It is divided into 40 ms frames, each of which is sub-divided into 6 slots. The DQPSK digital control channel used in IS-136, the TDMA (Time Division Multiple Access) Digital AMPS Cellular (D-AMPS) specification. |
| DCE | Data Communication Equipment | The devices and connections of a communications network that connect the communication circuit between the data source and destination (the Data Terminal Equipment or DTE). A modem is the most common kind of DCE. |
| DCS | Digital Cellular Service | See PCS. |
| DDE | Dynamic Data Exchange | A Windows protocol that allows communication between applications so that when a document is updated in one application, related information will be updated in other documents linked to it in this way. |
| Dead Tree Document | The paper version of a document available in both paper and electronic forms. | |
| DES | Data Encryption Standard | NIST-standard encryption technique that scrambles data into an unbreakable code for public transmission. It uses a binary number as an encryption key with 72 quadrillion possible combinations. The key, randomly chosen for each session, is used to create the encryption pattern for transmission. In the encrypt phase (Native DES) input data must have a block size of 64 bits (8 bytes) long and the key must also be 64 bits (only 56 are used). In the decrypt phase ciphertext block is input, and the key is the same as was used for encryption. Commercial encryption can cascade up to 3 such phases (Triple DES) for greater security. |
| DF | Direction Finding | The use of a directional aerial or phased array aerial to locate the direction (bearing) of a radio frequency source. |
| DIP | Dual In-Line Package | The most common type of package for small and medium scale integrated circuits, with up to about 48 pins. The pins hang vertically from the two long edges of the rectangular package, spaced at intervals of 0.1 inch. The pins fit through holes in the circuit board to which they are soldered or into a socket. |
| DIY | Do It Yourself | Usenet/Chat acronym/abbreviation |
| DLL | Dynamic Link Library | Re-usable software modules in Microsoft Windows. |
| DMA | Direct Memory Access | A facility of some architectures which allows a peripheral to read and write memory without intervention by the CPU. DMA is a limited form of bus mastering. |
| DNS | Domain Name System | A database system that translates an IP address into a domain name. For example, a numeric address like 232.452.120.54 can become something like xyz.com. |
| DoD | (US) Department of Defense | The mission of the Department of Defense is to provide the military forces needed to deter war and to protect the security of the country. The department's headquarters is at the Pentagon. |
| DPSK | Differential Phase Shift Keying | Common form of phase modulation used in modems. It does not require complex demodulation circuitry and is not susceptible to random phase changes in the transmitted waveform. |
| DSL | Digital Subscriber Line | A public network technology that delivers high bandwidth over conventional copper wiring at limited distances. There are four types of DSLs: ADSL, HDSL, SDSL, and VDSL. All are provisioned via modem pairs, with one modem located at a central office and the other at the customer site. Because most DSL technologies don't use the whole bandwidth of the twisted pair, there is room left for a voice channel. See also ADSL, HDSL, SDSL, and VDSL. |
| DSP | Digital Signal Processor | It converts analog signals into digital data and analyzes it using various algorithms such as Fast Fourier Transform. Once a signal has been reduced to numbers, its components can be isolated and analyzed more readily than in analog form. It is used in such fields as biomedicine, sonar, radar, seismology, speech and data communications. |
| DTC | Digital Traffic Channel | TDMA slotted 48 kbits/second DQPSK channel. The DTC was introduced with IS-54B, but has been greatly improved upon in IS-136 with a new voice coder and enhanced signaling capabilities. The 30 kHz TDMA traffic channel allows three simultaneous conversations. IS-136 has also added new control messages and expanded previous messages on the DTC, providing new services and supporting transparent extension of cellular services into the PCS band. |
| DTE | Data Terminal Equipment | A device which acts as the source and/or destination of data and which controls the communication channel. DTE includes terminals, computers, protocol converters, and multiplexors. |
| DVFO | Digital Variable Frequency Oscillator | An oscillator whose frequency is set by a presettable counter under program control. |
| DWDM | Dense Wave Division Multiplexing | DWDM makes optimum use of facilities by allowing fiber-optic links to carry several channels simultaneously, providing transmission capabilities four to sixteen times those of traditional time division multiplexed (TDM) systems. Use of DWDM allows providers to carry IP, ATM and SONET over the optical layer. |
| DWI | Driving While Intoxicated | Operating a vehicle while intoxicated is either a traffic violation (ticket is issued) or a Criminal Offense (arrest, court, prison sentence) depending on the relevant state laws. |
| E is for ... | ||
| ECMA | European Computer Manufacturers Association | Group of European computer vendors who have done substantial OSI standardization work. |
| EDI | Electronic Data Interchange | The electronic communication of operational data such as orders and invoices between organizations. |
| EIA | Engineering Industries Association | The EIA was formed over 50 years ago by a small group of companies to provide a common platform from which business development issues could be shared and resolved. Over the years, the association has continued to provide a network of advice and assistance that will promote the engineering industry in the UK, Europe and Global Markets. |
| EIA | Electronics Industry Association | A body which publishes "Recommended Standards" (RS) for physical devices and their means of interfacing. For example, RS-232 is their standard that defines a computer's serial port, connector pin-outs, and electrical signalling. |
| EISA | Extended Industry Standard Architecture | A PC bus that extends the ISA bus from 16 bits to 32 bits, but can still be used to plug in ISA expansion cards. Runs at up to 33 Mb/s. |
| EL | Electro Luminescent | Flat panel display that provides a sharp, clear image and wide viewing angle. It contains a powdered or thin film phosphor layer sandwiched between an x-axis and a y-axis panel. When an x-y coordinate is charged, the phosphor in that vicinity emits visible light. Phosphors are typically amber, but green is also used. |
| Emoticon | A typewritten picture of a facial expression, used in email and when communicating on the Internet, to indicate emotion. Example; the smiley :) or :-) | |
| ETACS | Extended Total ACcess System | The standard that analogue mobile phones use. |
| ETSI | European Telecommunications Standards Institute | Organization created by the European PTTs and the European Community (EC) to propose telecommunications standards for Europe.Under control of the EU, responsible for development of telecommunication standards for Europe. |
| Extranet | The part of a company or organization's internal computer network which is available to outside users with given access rights, for example, information services for customers. | |
| F is for ... | ||
| FAQ | Frequently Asked Questions | A document that provides answers to frequently asked questions on a specific topic |
| FCC | Federal Communications Commission | U.S. government agency that supervises, licenses, and controls electronic and electromagnetic transmission standards. |
| FDDI | Fiber Distributed Data Interface | Fiber Distributed Data Interface. LAN standard, defined by ANSI X3T9.5, specifying a 100-Mbps token-passing network using fiber-optic cable, with transmission distances of up to 2 km. FDDI uses a dual-ring architecture to provide redundancy. |
| Flame | Expression of a strong opinion or criticism, often directed at a specific person or group | |
| FM | Frequency Modulation | Transmission technique that blends the data signal into a carrier by varying (modulating) the frequency of the carrier. |
| FOFL | Falling On Floor Laughing | Usenet/Chat acronym/abbreviation |
| FR | Frame Relay | A protocol used across the interface between user devices (for example, hosts and routers) and network equipment (for example, switching nodes). Frame Relay is more efficient that X.25, the protocol for which it is generally considered a replacement |
| FSK | Frequency Shift Keying | Simple modulation technique that merges binary data into a carrier. It creates only two changes in frequency: one for 0, another for 1. |
| FTP | File Transfer Protocol (or Program) | A client/server protocol for exchanging files with a host computer or between network nodes. Usually part of the TCP/IP protocol stack, FTP is defined in RFC 959. Examples of ftp programs are Xmodem, Ymodem, Zmodem and Kermit. |
| FUD | (spreading) Fear, Uncertainty, and Disinformation | Usenet/Chat acronym/abbreviation |
| FWIW | For What It's Worth | Usenet/Chat acronym/abbreviation |
| FYI | For Your Information | Usenet/Chat acronym/abbreviation |
| G is for ... | ||
| Geek | A person who, for one reason or another, is considered socially unacceptable by the person speaking. A computer geek is someone who is socially inept but expert with computers. As computers become more important in the average person's life, this term becomes more often a compliment than an insult. | |
| GIF | Graphics Interchange Format | The GIF de facto standard is a device independent format developed by the CompuServe Information Service and H&R Block Company for the distribution and exchange of images over the network. It supports 8-bit color images up to 64K pixels on a side. Multiple images may reside on a file, and GIF provides very efficient packing and unpacking of files using the Lempel-Ziv & Welch compression algorithm. |
| GIX | Global Internet eXchange | A routing exchange point that helps networks all over the world to connect to the Internet. |
| GPRS | General Packet Radio Service | A packet-linked technology that enables high-speed wireless Internet and other data communications over a GSM network. |
| GPS | Global Positioning System | A system of satellites that transmit continually, which make it possible to identify earth locations through a receiving unit, by triangulation. |
| GSM | Global System for Mobile Communications | A world standard for digital cellular communications. GSM is a spec that was created by the Groupe Speciale Mobile and later became Global System for Mobile Communications or GSM 900 as it is normally referred to. |
| GUI | Graphical User Interface | Graphics-based user interface that incorporates icons, pull-down menus and a mouse. Macintosh, Windows, Presentation Manager (OS/2), OSF/Motif and Open Look are examples. See also CLI. |
| H is for ... | ||
| Hacker | 1. One who is knowledgeable about computers and creative in computer programming, usually implying the ability to program in assembly language or low-level languages. A hacker can mean an expert programmer who finds special tricks for getting around obstacles and stretching the limits of a system. 2. To some people it means an unconventional programmer or one who is not formally trained, or one who jerry-rigs programs (making temporary fixes that are not well-done). 3. At MIT, a "hack" means a practical joke, especially one that requires intelligence and technological skill to carry out. | |
| HD(D) | Hard Disk (Drive) | A sealed spinning disk with a magnetic coating. Information is written on it by magnetising tiny areas. The main permanent memory storage element in a computer, it is usually divided into several logical partitions (ex; C and D drives) and nowadays can hold over 8 Gigabytes of information. |
| HDLC | High- level Data Link Control | Bit-oriented synchronous data link layer protocol developed by ISO and corresponds to Layer 2 (the Data Link Layer) of the ISO 7-layered architecture. It is responsible for the error-free movement of data between network nodes. The job of the HDLC layer is to ensure that data passed up to the next layer has been received exactly as transmitted (i.e error free, without loss and in the correct order). Another important job is flow control, which ensures that data is transmitted only as fast as the receiver can receive it. Derived from SDLC, HDLC specifies a data encapsulation method on synchronous serial links using frame characters and checksums. See also SDLC. |
| HDML | Handheld Device Markup Language | This is a special mark-up language developed by Unwired Planet. The HDML language provides a set of commands or statements that specify how an UP.Phone interacts with a user. HDML statements display information on a phone, provide input options for the user and specify how the phone responds when the user presses keys. For example, an HDML statement can instruct a phone to display a prompt and allow the user to enter text. Whereas the fundamental structural unit of HTML is a page, in HDML the fundamental unit is a deck of cards. Each HTTP response from a Web server to an UP.Link is packaged in the form of a single HDML deck. A deck may contain one or more cards, each of which specifies a single interaction between the phone and the user. |
| HDSL | High-Speed (or Data Rate) Digital Subscriber Line | One of four DSL technologies. HDSL delivers 1.544 Mbps of bandwidth each way over two copper twisted pairs. Because HDSL provides T1 speed, telephone companies have been using HDSL to provision local access to T1 services whenever possible. The operating range of HDSL is limited to 12,000 feet, so signal repeaters are installed to extend the service. HDSL requires two twisted pairs, so it is deployed primarily for PBX network connections, digital loop carrier systems, interexchange POPs, Internet servers, and private data networks. See also ADSL, SDSL, and VDSL. |
| HTH | Hope This Helps | Usenet/Chat acronym/abbreviation |
| HTML | Hyper Text Markup Language | Used to create and format documents for display by a World Wide Web browser |
| HTTP | Hyper Text Transfer Protocol | The protocol most often used to transfer information from World Wide Web servers to browsers, which is why Web addresses begin with http://. Also called Hypertext Transport Protocol. |
| HUD | Head Up Display | An electro-optical unit that generates an image on the windscreen through an optical combiner. The driver's visual focus remains on the outside world as viewed through the combiner, while being provided with real-time navigation and vehicle performance information. |
| Hypertext | Text that has hyperlinks that link documents together. When hypertext is viewed with an interactive browser, certain words appear as highlighted by underlining or color; clicking on a highlighted link leads to another location with more information about the subject. The term was invented by Ted Nelson. | |
| I is for ... | ||
| IACP | International Association of Chiefs of Police | Since 1893, the International Association of Chiefs of Police has been serving the needs of the law enforcement community. Throughout those past
100 years we have been launching historically acclaimed programs, conducting ground-breaking research and providing exemplary programs and services to our members across the globe. Professionally recognized programs such as the FBI Identification Division and the Uniform Crime Records system can trace their origins back to IACP. In fact, the IACP has been instrumental in forwarding "breakthrough" technologies and philosophies from the early years of our establishment to now, as we approach the 21st century. From national use of fingerprint identification to partnering in a consortium on community policing, from establishing the FBI National Academy for state and local police with the FBI to gathering top experts in criminal justice, the government and education for summits on violent crime and homicide, IACP has realized our responsibility to positively impact the goals of law enforcement. See also IACP Technology Clearinghouse |
| IAE | In Any Event | Usenet/Chat acronym/abbreviation |
| ICBW | I Could Be Wrong (sometimes It Could Be Worse) | Usenet/Chat acronym/abbreviation |
| IDB | ITS Data Bus | An ITS Data Bus (IDB) is connected to the auto's multiplex bus through a gateway. This allows electronic device manufacturers to build a single, automotive version of their product that plugs in to the IDB on any auto. In addition, the IDB is independent of all auto systems, except for dc power, eliminating the need for a full electrical bench qualification. The gateway, under the control of the auto company, acts as a "firewall" allowing only authorized message traffic to pass between the auto's multiplex bus and the IDBs devices, ensuring safe operation of all vehicle systems. |
| IEC | International Electrotechnical Commission | Industry group that writes and distributes standards for electrical products and components. |
| IEE | Institution of Electrical Engineers | The IEE represents the profession of electrical, electronic, manufacturing and systems engineering and related sciences. |
| IEEE | Institute of Electrical and Electronic Engineers | The IEEE promotes the engineering process of creating, developing, integrating, sharing, and applying knowledge about electro- and information technologies and sciences for the benefit of humanity and the profession. |
| IETF | Internet Engineering Task Force | An international group of network designers, operators, vendors, and researchers who coordinate the management and evolution of the Internet, addressing issues of protocol and architecture. The IETF submits proposals for standards to the Internet Architecture Board. Essentially a volunteer organization of people who co-ordinate Internet standards, new documents, the chairs and the participants of the Working Groups. |
| IIRC | If I Recall Correctly | Usenet/Chat acronym/abbreviation |
| IMAP | Internet Message Access Protocol | A protocol that allows a user to perform certain electronic mail functions on a remote server rather than on a local computer. Through IMAP the user can create, delete, or rename mailboxes; get new messages; delete messages; and perform search functions on mail. A separate protocol is required for sending mail. Also called Internet Mail Access Protocol. |
| IMEI | International Mobile Equipment Identity | The unique electronic serial number of a GSM phone. |
| IMHO | In My Humble Opinion | Usenet/Chat acronym/abbreviation |
| IMNSHO | In My Not So Humble Opinion | Usenet/Chat acronym/abbreviation |
| IMO | In My Opinion | Usenet/Chat acronym/abbreviation |
| INDEO | INtel ViDEO | A way of recording, compressing, and decompressing video for playing on a computer. Invented by Intel, one of this software Codec for Video main applications is video conferencing. |
| Internet | A network of networks; a group of networks interconnected via routers. The Internet (with a capital I) is the world's largest internet. This worldwide information highway is comprised of thousands of interconnected computer networks, and reaches millions of people in many different countries. The Internet was originally developed for the United States military, and then became used for government, academic and commercial research and communications. The Internet is made up of large backbone networks (such as MILNET, NSFNET, and CREN), and smaller networks that link to them. The U.S. National Science Foundation maintains a major part of the backbone (NSFNET). The Internet functions as a gateway for electronic mail between various networks and online services. The World Wide Web facility on the Internet makes possible almost instantaneous exchange of information by linking documents around the world. Internet computers use the TCP/IP (Transmission Control Protocol/Internet Protocol). There are over six million hosts on the Internet: mainframes, minicomputers or workstations that support the Internet Protocol. The Internet is connected to computer networks worldwide that use various message formats and protocols; gateways convert these formats between networks so that the Internet functions as one big network. UNIX utilities such as FTP, Archie, Telnet, Gopher and Veronica have been widely used to access the Internet. The Internet sometimes appears to be amorphous and unregulated, but there are several administrative bodies: the Internet Architecture Board, which oversees technology and standards; the Internet Assigned Numbers Authority, which assigns numbers for ports and sockets, etc.; InterNIC, which assigns Internet addresses; the Internet Engineering and Planning Group, Internet Engineering Steering Group, and the Internet Society. | |
| Intranet | A local area network which may not be connected to the Internet, but which has some similar functions. Some organizations set up World Wide Web servers on their own internal networks so employees have access to the organization's Web documents. | |
| IOW | In Other Words | Usenet/Chat acronym/abbreviation |
| IP | Internet Protocol | See TCP/IP. |
| IPX | Internetwork Packet eXchange | A Novell NetWare network layer (Layer 3) protocol for delivering messages in datagram format. IPX is similar to IP and XNS. |
| IR | Infra-Red | Invisible band of radiation at the low-frequency (below red) end of the light spectrum. Often used for short range data communications as in remote controls. |
| IRC | Internet Relay Chat | Worldwide real-time conferencing on the Internet, reached by Telnetting to an IRC server. There are hundreds of IRC channels for many different subjects, from many countries. There are purely social chat rooms, and channels dedicated to more serious purposes. |
| IrDA | Infrared Data Association | The IrDA is an association of over 150 companies world wide focused on providing IR standards to ensure the quality and interoperability of the Infrared Technology. IrDA is an International Organization that creates and promotes interoperable, low cost infrared data interconnection standards that support a walk-up, point-to-point user model. The standards support a broad range of appliances, computing and communications devices. |
| IRL | In Real Life | Usenet/Chat acronym/abbreviation |
| IRQ | Interrupt ReQuest | The name of an input found on many processors which causes the processor to suspend normal instruction execution temporarily and to start executing an interrupt handler routine. |
| ISA | Industry Standard Architecture | A PC expansion bus (old) used for modems, video displays, speakers, and other peripherals. PCs with ISA commonly have some 8-bit and some 16-bit expansion slots. Runs at about 8 Mb/s. |
| ISDN | Integrated Services Digital Network | International telecommunications standard for transmitting voice, video and data over a digital line. It uses 64Kbps circuit-switched B (Bearer) channels to carry voice and data and uses a separate D (Data) channel to carry control signals via a packet-switched network. This out-of-band D
channel allows a variety of services to be provided, including call forwarding, call waiting and advice of charge. The two types of service
are: Basic Rate Interface (BRI) 144Kbps. Includes two B channels and one 16Kbps D channel (2B+D). Primary Rate Interface (PRI) 1.544Kbps. In North America, it includes 23 B channels and one 64Kbps D channel (23B+D), equivalent to T1. In Europe, it includes 30 B channels and one 64Kbps D channel (30B+D), equivalent to European E1 service. |
| ISO | The International Organization for Standardization
(ISO) is a worldwide federation of national standards bodies from some 130 countries, one from each country. ISO is a non-governmental organization established in 1947. The mission of ISO is to promote the development of standardization and related activities in the world with a view to facilitating the international exchange of goods and services, and to developing cooperation in the spheres of intellectual, scientific, technological and economic activity. ISO's work results in international agreements which are published as International Standards. ISO's name - is not an acronym. "ISO" is a word, derived from the Greek isos, meaning "equal", which is the root of the prefix "iso-" that occurs in a host of terms, such as "isometric" (of equal measure or dimensions) and "isonomy" (equality of laws, or of people before the law). From "equal" to "standard", the line of thinking that led to the choice of "ISO" as the name of the organization is easy to follow. In addition, the name ISO is used around the world to denote the organization, thus avoiding the plethora of acronyms resulting from the translation of "International Organization for Standardization" into the different national languages of members, e.g. IOS in English, OIN in French (from Organisation internationale de normalisation). Whatever the country, the short form of the Organization's name is always ISO. | |
| ISP | Internet Service Provider | A company that provides Internet access and associated services such as a web page/s, an email address, ftp facilities, Usenet news groups access, dial-up modems and so on. |
| ISTR | I Seem To Recall | Usenet/Chat acronym/abbreviation |
| ISWYM | I See What You Mean | Usenet/Chat acronym/abbreviation |
| ITS | Intelligent Transportation Systems | ITS promotes advanced road usage and greater ease in transportation by integrating people, roads, and vehicles through information technology. It will create road transportation which improves safety, efficiency, and comfortableness, also contributing to environmental preservation. |
| ITU | International Telecommunication Union | Former CCITT. The ITU headquartered in Geneva, Switzerland is an international organisation within which governments and the private sector coordinate global telecom networks and services. ITU activities include the coordination, development, regulation and standardisation of telecommunications and organisation of regional and world telecom events. Split in 2 groups: ITU-R: Radio communication Sector ITU-T: Telecommunication Standardisation Sector |
| J is for ... | ||
| Java | A cross-platform programming language from Sun Microsystems that can be used to create animations and interactive features on World Wide Web pages. Java programs are embedded into HTML documents. | |
| JavaScript | A cross-platform WWW scripting language from Netscape Communications, very popular because it is simple and easy to learn. It can be included in an HTML file by using the tag <script language="JavaScript">. | |
| JPEG | Joint Photographic Experts Group | JPEG (pronounced "jay-peg") is a standardized image compression mechanism using DCT (Discrete CosineTransformation), high frequency filtering and Huffmann coding. The name comes from the committee that wrote the standard. JPEG is designed for compressing either full-color or gray-scale images of natural, real-world scenes. It works well on photographs, naturalistic artwork, and similar material; not so well on lettering, simple cartoons, or line drawings. JPEG provides lossy compression by segmenting the picture into small blocks which are divided to get the desired ratio; the process is reversed to decompress the image. JPEG uses the JPEG File Interchange Format, or JFIF. JPEG handles only still images, but there is a related standard called MPEG for motion pictures. |
| K is for ... | ||
| KERNEL | The essential part of a program or operating system, that performs the basic functions and also provides the interface to the hardware. | |
| L is for ... | ||
| LAN | Local Area Network | A network that connects computers that are close to each other, usually in the same building, linked by a cable. The most popular LAN type is Ethernet, a 10 Mbps/100Mbps standard that works with 10BaseT, 10Base2, or 10Base5 cables. |
| LAPB | Link Access Procedure, Balanced | Data link layer protocol in the X.25 protocol stack. LAPB is a bit-oriented protocol derived from HDLC. See also HDLC and X.25. |
| LCD | Liquid Crystal Display | A type of display used on digital watches, calculators, and laptop computers. LCDs are lighter and consume much less power than other computer displays. Liquid crystals are rod-shaped molecules which spiral when they are exposed to an electrical charge. Polarized light passing through the layer of liquid crystal cells is twisted along the spiral path of the molecules. The light then passes through a series of filters which block light vibrating at certain angles and allow light vibrating at other angles to pass through; thus the color of each pixel can be controlled |
| Link Rot | The process by which links on a web page become obsolete as the sites they're connected to change location or die. | |
| Li-Ion | Lithium Ion | A high energy density secondary (rechargeable) battery. |
| LLC | Logical Link Control | Higher of the two data link layer sublayers defined by the IEEE. The LLC sublayer handles error control, flow control, framing, and MAC-sublayer addressing. The most prevalent LLC protocol is IEEE 802.2, which includes both connectionless and connection-oriented variants. |
| LMDS | Local Multipoint Distribution Service | Located in the 28 GHz and 31 GHz bands, LMDS is a broadband radio service designed to provide two-way transmission of voice, high-speed data and video (wireless cable TV). FCC rules prohibit incumbent local exchange carriers and cable TV companies from offering in-region LMDS. |
| LPC | Linear Predictive Coding | Linear Predictive Coding (LPC) is one of the most powerful speech analysis techniques, and one of the most useful methods for encoding good quality speech at a low bit rate. It provides extremely accurate estimates of speech parameters, and is relatively efficient for computation. See this tutorial. |
| Lurker | A visitor to an online discussion who reads other people's postings but does not contribute. Lurking is a good way for a beginner to get familiar with a newsgroup or forum. | |
| M is for ... | ||
| MAC | Media Access Control | Lower of the two sublayers of the data link layer defined by the IEEE. The MAC sublayer handles access to shared media, such as whether token passing or contention will be used. |
| MAN | Metropolitan-Area Network | Network that spans a metropolitan area. Generally, a MAN spans a larger geographic area than a LAN, but a smaller geographic area than a WAN. |
| MAP | Manufacturing Automation Protocol | Network architecture created by General Motors to satisfy the specific needs of the factory floor. MAP specifies a token-passing LAN similar to IEEE 802.4. |
| MCM | Multi Chip Module | The MCM packages bare chips on a ceramic substrate to achieve very high density, complex modules. For example, a complete Pentium processor core system the size of a credit card. |
| MCI | Media Control Interface | Part of the Multimedia Extensions to Windows 3.0. It is intended to provide a high-level scripting interface to control all sorts of media devices. To provide high-level media-streaming services it works with ActiveMovie. |
| MCU | Micro Controller Unit | An integrated unit that includes a microprocessor, program and data memory, peripheral interfaces, timers and so on. |
| MDC | Motorola Data Communications | Protocol designed and used by Motorola for transmitting data over a 3kHz analog voice radio channel. MDC-600 was 600 baud FSK and MDC-1200 was 1200 baud MSK (Minimum Shift Keying). Also MDC-4800. |
| MID | Message IDentification character | Part of the Message Structure in SAE J1708. The one character MID field ranges from 0 to 255. A MID value in the field is a unique identifier. It pertains to a device or transmitter and indicates the characteristics of the data following the MID value. |
| MIME | Multi-purpose Iinternet Mail Extensions | Extensions to the Internet mail format that allow it to carry multiple types of data (binary, audio, video, graphics, etc.) as attachments to email messages. An Internet messages, as defined by RFC 822, consists of two parts: a header and a body. MIME defines a set of five extensions to RFC 822: a content type header field, a content transfer encoding header field, a MIME version header field, an optional content ID header field, and optional content descriptions header field. MIME has become the standard for attaching non-text files to e-mail messages in a way that allows the attachment to be received intact over a network. |
| MJPEG | Motion JPEG | The compression format used for digital video in the mid 1990's. The compression within each frame of an MJPEG file is compressed in an identical way to single frame JPEG. Each frame of the moving vision (the M of M JPEG) is compressed as a single frame with no reference to the frame before or after - essential for simple accurate editing. MPEG (Motion Picture Experts Group) compresses between frames (inter-frame compression) in addition to the intra-frame compression, making accurate editing difficult. Rather, MPEG is a useful distribution (post editing) media. An MJPEG file differs from a JPEG file only in that multiple frames are present in the one file. |
| MMP | Mobile Message Protocol | Wireless data protocol originally designed and used by MDI which was inherited by Motorola. 4,800 bps FSK. |
| MPEG | Motion Picture Experts Group | The Moving Picture Experts Group (MPEG) is a working group of ISO/IEC in charge of the development
of international standards for compression, decompression, processing, and coded representation of moving pictures, audio and their combination. So far MPEG has produced: MPEG-1, the standard for storage and retrieval of moving pictures and audio on storage media; MPEG-2, the standard for digital television; MPEG-4 version 1, the standard for multimedia applications; and is now developing: MPEG-4 version 2 (to be approved December 1999); MPEG-7 the content representation standard for multimedia information search, filtering, management and processing (to be approved July 2001). |
| MUX | MUltipleX (or Multiplexer) | A device, process or network that merges multiple communication paths into a single signal path. |
| N is for ... | ||
| NBS | National Bureau of Standards | Organization that was part of the U.S. Department of Commerce. Now known as NIST. See also NIST. |
| Nerd | 1. A creature in a Dr. Seuss children's book, If I Ran the Zoo. 2. A socially inept or unattractive person. 3. A person who is more interested in pursuing intellectual interests than in keeping up with trends in fashion. Since the Internet revolution, "nerd" has become a less pejorative term, and "computer nerd" is even used with admiration. | |
| Newsreader | A software application used to read and post Usenet messages | |
| NFS | Network File System | As commonly used, a distributed file system protocol suite developed by Sun Microsystems that allows remote file access across a network. There are alternatives, including NFS variants such as the far more secure DES-NFS and kerebosized NFS. NFS operates over the TCP/IP protocol used by Telnet, FTP and WWW browsers. |
| NiMH | Nickel Metal Hydride | A secondary (rechargeable) battery that replaced the Nickel-Cadmium (Ni-Cad) battery. Has higher energy storage and does not suffer from the memory effect. |
| NIST | National Institute of Standards and Technology | Formerly the NBS, this U.S. government organization supports and catalogs a variety of standards. See also NBS. |
| NOS | Network Operating System | For example; Novell, Lan Manager, Windows NT |
| NRN | No Reply Necessary | Usenet/Chat acronym/abbreviation |
| NRZ | Non Return to Zero | NRZ signals maintain constant voltage levels with no signal transitions (no return to a zero-voltage level) during a bit interval. See also NRZI. |
| NRZI | Non Return to Zero Inverted | NRZI signals maintain constant voltage levels with no signal transitions (no return to a zero-voltage level), but interpret the presence of data at the beginning of a bit interval as a signal transition and the absence of data as no transition. See also NRZ. |
| NYCTMI | Now You Come To Mention It | Usenet/Chat acronym/abbreviation |
| O is for ... | ||
| OBD-II | On Board Diagnostics II | Established by CARB (California Air Resources Board) and requires the implementation of diagnostic tools for emission-related systems. OBD-II specifies that stored fault codes be available through a diagnostic port via a standard protocol. Currently, OBD-II specifies J1850 and the European standard, ISO 9141-2. |
| ODBC | Open Data Base Connectivity | An interface that makes it possible to access different database systems with a common language. ODBC is based on CLI (Call Level Interface); there are ODBC drivers and development tools for Windows, Macintosh, UNIX, and OS/2. |
| OIC | Oh, I See! | Usenet/Chat acronym/abbreviation |
| OLE | Object Linking Environment | Windows standard for object embedding |
| OOI | Out Of Interest | Usenet/Chat acronym/abbreviation |
| OOTB | Out Of The Box (brand new) | Usenet/Chat acronym/abbreviation |
| OS | Operating System | Operating systems provide a software platform on top of which other programs, called application programs, can run. Operating systems also perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. |
| OSF | Open Software Foundation | The Open Software Foundation was merged with the X/Open Company Ltd. in February 1996 to form the Open Group. The Open Group is committed to delivering greater business efficiency by bringing together buyers and suppliers of information systems to lower the barriers of integrating new technology across the enterprise. Organizations wishing to reduce the time, cost, and risk of implementing new solutions which integrate within and between enterprises need The Open Group as their critical partner to ensure that multi-vendor information technology meets the demands and needs of customers. This is achieved through the development and deployment of frameworks, policies, “best practice”, and standards in pursuit of the IT DialTone™ vision - the concept of making all technology as open and accessible as using a telephone. |
| OSI | Open Systems Interconnect | ISO 7-layer protocol method, the layers being (from bottom up) Physical, Data Link, Network, Transport, Session, Presentation, Applications |
| OTOH | On The Other Hand | Usenet/Chat acronym/abbreviation |
| OTTH | On The Third Hand | Usenet/Chat acronym/abbreviation |
| P is for ... | ||
| PBX | Private Branch eXchange | A telephone exchange used within an organization and located on the premises; an example would be the main switchboard in a hospital. |
| PC | Personal Computer | A general-purpose single-user computer designed to be operated by one person at a time. |
| PCI | Peripheral Component Interconnect | The PCI Local Bus is a high-performance 32/64 bit bus that provides rates of up to 133 Mb/s and a processor-independent data path between the PCI CPU and high-speed PCI peripherals. |
| PCM | Pulse Code Modulation | Technique for digitizing speech by sampling the sound waves and converting each sample into a binary number. It uses waveform coding that samples a 4KHz bandwidth 8,000 times a second. Each sample is an 8 bit number, resulting in 64K bits of data per second. See also ADPCM. |
| PCMCIA | Personal Computer Memory Card International Association, also People Can't Memorize Computer Industry Acronyms | A Sunnyvale, California nonprofit trade association created to standardize the connection of peripherals to portable computers. PCMCIA developed the PC Card (often called the PCMCIA card), a lightweight, removable module about the size of a credit card that adds features to a portable computer. |
| PCN | Personal Communications Network | See PCS. |
| PCS | Personal Cellular Service | DCS, PCN and PCS are all another standard of GSM using the 1800 MHz FM carrier frequency. There are advantages over GSM being that there are more call channels at 1800Mhz but the standard defines that the signal power is only 1 watt compared with 4 watts of a GSM 900 telephone. PCN/DCS is normally refered to as GSM1800 and PCS is normally refered to as GSM 1900 as it operates at 1900 MHz . In North America the group of three digital cellular phone technologies, GSM 1900, CDMA IS-95, and TDMA IS-136, are also collectively known as PCS. By connecting a PCS cellular phone to a laptop PC, you can wirelessly use data applications to do Internet browsing, corporate LAN/database access, fax, short messaging service and email. |
| PDA | Personal Digital Assistant | A battery driven, hand-held computer with (usually) a small (1/4 or 1/2 vga) display and pen input. |
| Perl | Perl is a high-level programming language with an eclectic heritage written by Larry Wall and a cast of thousands. It derives from the ubiquitous C programming language and to a lesser extent from sed, awk, the Unix shell, and at least a dozen other tools and languages. Perl's process, file, and text manipulation facilities make it particularly well-suited for tasks involving quick prototyping, system utilities, software tools, system management tasks, database access, graphical programming, networking, and world wide web programming. These strengths make it especially popular with system administrators and CGI script authors, but mathematicians, geneticists, journalists, and even managers also use Perl. | |
| PID | Parameter IDentification character | The SAE J1587 functions on the data link layer as the addressing or routing service. Instead of using the term data characters, it organizes an address by parameters. A parameter consists of a Parameter Identification (PID) character and a series of data characters. Currently, SAE J1587 uses 511 parameters to specify various activities associated with a public transportation vehicle. |
| POP | Point Of Presence | The closest site where a user can connect to an Internet server or other remote server; or, the location where a line from a long-distance telephone carrier makes a local connection. |
| POP | Post Office Protocol | A protocol used by mail clients to download messages from a mail server on the Internet. |
| POP | Point Of Purchase | A terminal or vending machine in a store or shopping mall where a customer can view products with their prices and select items to buy. |
| POS | Point Of Sale | The time and place in which a transaction is made. Point of sale computer systems include cash registers, optical scanners, magnetic card readers, and special terminals. Reading product tags, updating inventory, and checking credit are some of the operations performed at the point of sale. |
| PPP | Point to Point Protocol | A protocol for communication between computers using TCP/IP, over standard telephone lines, ISDN, and other high-speed connections. PPP was developed by the Internet Engineering Task Force (IETF) and is defined in RFC 1171. It can be used to connect a computer to the Internet, for services such as the World Wide Web and email. PPP is faster than SLIP and has better error correction; it can be used with both synchronous and asynchronous transmission. |
| PSK | Phase Shift Keying | See DPSK. |
| pSOS | pSOSystem is a complete scaleable real-time operating system for embedded applications from Integrated System Inc. pSOSystem includes support for single processor (pSOS+), multi-processor (pSOS+m), file management (pHILE), TCP/IP communication (pNA), streams communication (OpEN), graphics, JAVA, HTTP etc. | |
| PSTN | Public Switched Telephone Network | A voice and data communications service for the general public which uses switched lines. |
| PWM | Pulse Width Modulation | Class B Multiplexing - In the US, the SAE adopted J1850 as the standard protocol for Class B networks. J1850 was a joint effort among the Big Three (Ford, GM, Chrysler) and is actually a combination of GM's Class 2 protocol and Ford's SCP (Standard Corporate Protocol). The resulting standard has two basic versions. The first is a 10.4 Kb/s VPW (Variable Pulse Width) type which uses a single bus wire. The second is a 41.6 Kb/s PWM (Pulse Width Modulation) type which uses a two-wire differential bus. Chrysler adopted a variation of the 10.4Kb/s version. |
| Q is for ... | ||
| QPSK | Quadrature Phase Shift Keying | Data modulation method using 4 phases of the carrier to represent the signal states. Used in TDMA, D-AMPS and other systems. |
| QWERTY | The qwerty keyboard is the standard English language typewriter and computer keyboard. Q, w, e, r, t and y are the letters on the top left, alphabetic row. It was originally designed to slow typing to prevent the keys from jamming. | |
| R is for ... | ||
| RD-LAP | Radio Data Link Access Procedure | A narrowband data communications protocol optimised for data transfer in the land-mobile environment. |
| RFC | Request For Comments | Every IETF standard is published as an RFC (a "Request For Comments", but everyone just calls them RFCs), and every RFC starts out as an Internet Draft (often called an "I-D"). |
| RISC | Reduced Instruction Set Computer | Computer architecture that reduces chip complexity by using simpler instructions. RISC compilers have to generate software routines to perform complex instructions that were previously done in hardware by CISC computers. In RISC, the microcode layer and associated overhead is eliminated. RISC keeps instruction size constant, bans the indirect addressing mode and retains only those instructions that can be overlapped and made to execute in one machine cycle or less. The RISC chip is faster than its CISC counterpart and is designed and built more economically. |
| RLC | Random Length Code | Encryption method where all data is compressed, tokenized, and stored in random length records. |
| RLC | Run Length Code | A FAX transmission treats each facsimile line as a series of white and black runs. The runs are coded based on their length, and the code is transmitted instead of the full bit map. The code is called the run length code and the procedure is termed run length encoding. For instance, if the FAX detects 40 black spots, instead of sending 40-dots, it will send 40b. This will save significantly. This applies to the white spots. As it will send the whites and blacks alternatively, the code consists of a series of numbers on whites and blacks. |
| ROTFL | Rolling On The Floor Laughing | Usenet/Chat acronym/abbreviation |
| RSA | Rivest, Shamir, Adleman | in 1978, Ron Rivest, Adi Shamir, and Leonard Adleman developed a public-key system that addressed these concerns. This algorithm is now known as RSA (after its inventors). In the nearly 20 years since its creation, RSA has developed to become the de facto standard of encryption in the computer world. In fact, RSA is now the only public-key system in wide use. From web browsers such as Netscape to email encryption programs such as PGP, RSA is now everywhere. |
| RTE | Run-Time Environment | The set of routines or procedures that are active all the time in an operating system and provide standard services for other applications or modules. For example, real-time thread management, stack management, garbage collection and input/output services. |
| RTFM | Read The Fine Manual | Usenet/Chat acronym/abbreviation. A retort to another user who has asked a common question that can be answered by reading the available documentation. (The word Fine is commonly replaced by a more vulgar substitute) |
| RTOS | Real Time Operating System | Is multi-threaded and preemptible with predictable thread synchronisation mechanisms, a system of priority inheritance has to exist and the interrupt latency (i.e. time from interrupt to task run) has to be compatible with application requirements and has to be predictable. |
| S is for ... | ||
| SAE | Society of Automotive Engineers | About SAE - What do cars, aircraft, trucks, off-highway equipment, engines, materials, manufacturing, and fuels have in common? SAE. The Society of Automotive Engineers is your one-stop resource for technical information and expertise used in designing, building, maintaining, and operating self-propelled vehicles for use on land or sea, in air or space. |
| SDH | Synchronous Digital Hierarchy | European standard that defines a set of rate and format standards that are transmitted using optical signals over fiber. SDH is similar to SONET, with a basic SDH rate of 155.52 Mbps, designated at STM-1. See also SONET and STM-1. |
| SDLC | Synchronous Data Link Control | SNA data link layer communications protocol. SDLC is a bit-oriented, full-duplex serial protocol that has spawned numerous similar protocols, including HDLC and LAPB. See also HDLC and LAPB. |
| SDSL | Single-line Digital Subscriber Line | One of four DSL technologies. SDSL delivers1.544 Mbps both downstream and upstream over a single copper twisted pair. The use of a single twisted pair limits the operating range of SDSL to 10,000 feet. See also ADSL, HDSL, and VDSL. |
| SID | System IDentification | A number uniquely identifying a cellular system. |
| SIM | Subscriber Identity Module | A smart card that contains all your details and is a type of electronic key to your phone. On analogue phones this is built onto an electronic chip inside the phone and cannot be removed. The SIM holds details of what the operator has allowed you to do, such as access to the Fax and Data Service, Short Message Service, and any other service that requires the payment of a subscription the provider updates this card to enable the services on your phone. The SIM also holds your phone number and several phone number memories. So you could put it into another phone and it would assume the identity of your phone. |
| SLIP | Serial Line Internet Protocol | Standard protocol for point-to-point serial connections using a variation of TCP/IP. SLIP makes it possible for a computer to communicate with other computers by means of a dial-up connection; for example, a serial port hooked to a modem that makes a connection between two local area networks or is used to access the Internet and World Wide Web. Predecessor of PPP. |
| SMS | Short Message Service | The Text Message service on digital cellular phones. A message of not longer that 160 characters that can be sent to another digital cell phone usually on your home network but some networks will allow inter-network SMS facilities. The service operates by using the signalling channel used by the digital cellular phone systems (GSM/PCN) the text is converted to a code transmitted to the Message centre it then reads the destination number and sends the code to that phone where it is then converted back so that it can be read. |
| SNA | Systems Network Architecture | Large, complex, feature-rich network architecture developed in the 1970s by IBM. Similar in some respects to the OSI reference model, SNA is essentially composed of seven layers: data flow control layer, data link control layer, path control layer, physical control layer, presentation services layer, transaction services layer, and transmission control layer. |
| SNAFU | Situation Normal, All Fouled Up | Usenet/Chat acronym/abbreviation |
| SNMP | Simple Network Management Protocol | A protocol for Internet network management services. It is formally specified in a series of related RFC documents. |
| SONET | Synchronous Optical NETwork | High-speed (up to 2.5 Gbps) synchronous network specification developed by Bellcore and designed to run on optical fiber. STS-1 is the basic building block of SONET. Approved as an international standard in 1988. |
| SPAM | See UCE | |
| SQL | Structured Query Language | A language used to create, maintain, and query relational databases. It is an ISO and ANSI standard. SQL uses regular English words for many of its commands, which makes it easy to use. It is often embedded within other programming languages. |
| SS | Spread Spectrum | Jamming-resistant and initially devised for military use, this radio transmission technology "spreads" information over a wide bandwidth using Frequency Hopping or Direct Sequence for interference tolerance. Mostly uses 2.4GHz unlicensed band and provides 1-2 Mbps with IEEE 802.11 wireless LAN protocol. |
| SSI | Server Side Includes | Web servers support a standard set of commands called server-side includes. Server-side includes (or parsed html) are embedded in comments and can be used to include other resources in the HTML to be delivered to the client. Web pages containing SSI tags are normally suffixed .shtml |
| SSL | Secure Sockets Layer | The Handshake Protocol developed by Netscape Communications Corporation to provide security and privacy over the Internet. The protocol supports server and client authentication. The SSL protocol is application independent, allowing protocols like HTTP (HyperText Transfer Protocol), FTP (File Transfer Protocol), and Telnet to be layered on top of it transparently. The SSL protocol is able to negotiate encryption keys as well as authenticate the server before data is exchanged by the higher-level application. The SSL protocol maintains the security and integrity of the transmission channel by using encryption, authentication and message authentication codes. |
| STM-1 | Synchronous Transport Module level 1 | One of a number of SDH formats that specifies the frame structure for the 155.52-Mbps lines used to carry ATM cells. |
| STN | Super Twisted Nematic | Liquid crystal material used in modern LCD's to provide superior contrast. |
| STS-1 | Synchronous Transport Signal level 1 | Basic building block signal of SONET, operating at 51.84 Mbps. Faster SONET rates are defined as STS-n, where n is a multiple of 51.84 Mbps. |
| SVGA | Super Video Graphics Array | A video display standard for color monitors, defined by VESA. SVGA monitors display up to 16.7 million colors with resolutions up to 1,280 x 1,024 pixels, and are good for multimedia applications. |
| T is for ... | ||
| TACS | Total Access Communications System | Original UK analog cellular system that was based on the US AMPS cellular system. Had either 600 or 1000 channels (42 control, 558 or 958 voice) |
| TANSTAAFL | There Ain't No Such Thing As A Free Lunch | Usenet/Chat acronym/abbreviation |
| TCP/IP | Transmission Control Protocol/Internet Protocol | The Transmission Control Protocol (TCP) on top of the Internet Protocol (IP). These protocols were developed by DARPA to enable communication between different types of computers and computer networks. The Internet Protocol is a connectionless protocol which provides packet routing. TCP is connection-oriented and provides reliable communication and multiplexing. |
| TE | Transfer-Extension | The TE request-header field indicates what extension transfer-codings a client (browser) is willing to accept in the response from a server to an HTTP/1.1 message. The TE header field only applies to the immediate connection. |
| TIA | Thanks In Advance | Usenet/Chat acronym/abbreviation |
| TDMA | Time Division Multiple Access | A multiplexing technology used with satellites and cellular phones, in which multiple channels of data are interleaved (each signal is assigned to a different time interval, and the signals are transmitted by taking turns). |
| TETRA | Trans-European Trunked Radio | This is an open European standard for digital radio - designed primarily to meet the requirements of the emergency services. It is designed as a professional radio system and as such compliments the facilities offered by radio telephony systems such as GSM. |
| TFT | Thin Film Transistor | Active Display LCD, usually color, where each pixel has its own switching transistor. Provides best contrast. |
| Trojan horse | A program that appears to be useful and harmless but which has harmful side effects such as destroying data or breaking security on the system on which it is run. It is similar to a virus except that it does not propagate itself as a virus does. | |
| TTI | Texas Transportation Institute | TTI's mission is to solve transportation problems through research, to transfer technology, and to develop diverse human resources to meet the transportation challenges of tomorrow. |
| TTYL | Talk To You Later | Usenet/Chat acronym/abbreviation |
| TWIMC | To Whom It May Concern | Usenet/Chat acronym/abbreviation |
| TYVM | Thank You Very Much | Usenet/Chat acronym/abbreviation |
| U is for ... | ||
| UART | Universal Asynchronous Receiver Transmitter | Electronic circuit that transmits and receives data on a serial port. It converts bytes into serial bits for transmission, and vice versa, and generates and strips the start and stop bits appended to each character. |
| UCE | Unsolicited Commercial E-mail (also known as SPAM) | Usenet/Chat acronym/abbreviation |
| UDP | User Datagram Protocol | A communications protocol for the Internet network layer, transport layer, and session layer, which makes it possible to send a datagram message from one computer to an application running in another computer. Like TCP (Transmission Control Protocol), UDP is used with IP (the Internet Protocol). Unlike TCP, UDP is connectionless and does not guarantee reliable communication; the application itself must process any errors and check for reliable delivery. |
| UL | Underwriters Laboratories | Independent agency within the United States that tests product safety. |
| Unix | A multi-user, multitasking operating system developed by Ken Thompson, Dennis Ritchie, and others and originally licensed by AT&T's Bell Laboratories. It was originally designed for minicomputers, then revised for use on mainframes and personal computers. There are now many versions of UNIX which can be used on many different platforms. UNIX is written in the C programming language, which was also developed at AT&T. Because it allows multiple programs to run simultaneously and multiple users to access a single computer, it has been used by universities and businesses where many people use the same computer. It is the most commonly used operating system for Internet nodes. | |
| URI | Universal Resource Identifier | A user is requesting a resource, that is a combination of media types, text, graphics, language and so on. A resource is an entity identified by an URI as defined by RFC 2396. An HTTP server provides access to different representations of the resource within its namespace. Each representation is in the form of a sequence of bytes with a defined media type, character set, encoding, etc. Each resource may be associated with from zero, one or more representations at a given time. If multiple representations are available, the resource is referrred to as negotiable and each of its representations is termed a variant. |
| URL | Uniform (or Universal) Resource Locator | The address of a web document or resource. The standard format is protocol://domain/dir (opt)/.../name. Protocol can be http, ftp, telnet, news etc. Domain is normally www.company.com for a commercial organisation or www.organisation.org for a special interest group or www.university.edu for an educational establishment, but the www may often not be used. If the domain is outside the USA than a country code is added on like il for Israel. The document name usually has a suffix such as html or doc or txt or gif or jpg. |
| USB | Universal Serial Bus | This is used to connect various input/output devices together and to a controller. USB has two data rates, 12Mbps for devices requiring increased bandwidth, and 1.5 Mbps for lower-speed devices. USB uses a "tiered star topology" which means that some USB devices--called USB "hubs"--can serve as connection ports for other USB peripherals. Only one device needs to be plugged into the controller. Other devices can then be plugged into the hub. USB hubs may be embedded in peripheral devices, stand-alone hubs can also be used. Hubs feature an upstream connection (pointed toward the controller) as well as multiple downstream ports to allow the connection of additional peripheral devices. Up to 127 USB devices can be connected together in this way. |
| USDOT | United States Department Of Transportation | The Department of Transportation is the Federal steward of the Nation's transportation
system and speaks for transportation in the Federal government. Created in 1967, DOT brought under one umbrella a myriad of transportation missions and programs, some of which have been in existence since the 1700s. The Department employs about 100,000 civilian and military people deployed across the country and the world. It includes the OST as well as the following modal administrations: Bureau of Transportation Statistics National Highway Traffic Safety Administration, Federal Aviation Administration Research and Special Programs Administration, Federal Highway Administration St. Lawrence Seaway Development Corporation, Federal Railroad Administration Surface Transportation Board, Federal Transit Administration Transportation Administrative Service Center and Maritime Administration United States Coast Guard |
| Usenet | Users' network | A giant public bulletin board system on the Internet for news and electronic mail. Usenet was started in 1979 by graduate students at Duke University and the University of North Carolina, using the UUCP communications protocol. It now has over 12,000 discussion areas which cover every imaginable topic and are read by millions of people all over the world. Messages and news articles are posted and users respond by email. In hot discussion areas, hundreds of messages a day may be posted. Types of Usenet groups are comp (about computers), news (about newsgroups), rec (on sports and hobbies), sci (science), soc (social), talk (discussions), misc (miscellaneous), and alt (alternative newsgroups). |
| UUCP | Unix-to-Unix Copy Program (or Protocol) | A Unix protocol that makes it possible to copy a file from one Unix computer to another via a telephone line or direct connection. It is used for Usenet news and electronic mail. Unlike TCP/IP, UUCP requires that a session be established between the two computers in order to transfer files. |
| UUencoding | A Unix program that encodes binary data, 8-bit text files, and some other file formats into 7-bit ASCII files for transmission over the Internet and via email. It was originally used with UUCP. The uudecode program converts the files back into their original format. Uuencoded files have .uu or .uue as a suffix. | |
| V is for ... | ||
| V24 | ITU-T standard for a physical layer interface between DTE and DCE. V.24 is essentially the same as the EIA/TIA-232 standard. | |
| V35 | ITU-T standard describing a synchronous, physical layer protocol used for communications between a network access device and a packet network. V.35 is most commonly used in the United States and in Europe, and is recommended for speeds up to 48 Kbps. | |
| VAN | Vehicle Area Network | Older European vehicle bus standard, replaced by CAN. |
| VDSL | Very-high-data-rate Digital Subscriber Line | One of four DSL technologies. VDSL delivers 13 Mbps to 52 Mbps downstream and 1.5 Mbps to 2.3 Mbps upstream over a single twisted copper pair. The operating range if VDSL is limited to 1,000 to 4,500 feet. See also ADSL, HDSL, and SDSL. |
| VESA | Video Electronics Standards Association | An organization which sets standards for video and multimedia in PCs. VESA established the Super VGA (SVGA) standard and the VESA Local Bus. VESA is headquartered in San Jose, California, and its members are PC vendors. |
| VGA | Video Graphics Array | A video display standard for color monitors that superseded CGA and EGA. VGA monitors display 16 colors at a resolution of 640 x 480 pixels, the minimum standard display. The vertical scan frequency is around 56Hz to 60Hz. For multimedia applications, it is better to have Super VGA. |
| Virus | A program that infects a computer by atttaching itself to another program, and propagating itself when that program is executed. A computer can become infected by files downloaded over a network, or by the installation of new software or floppy disks that are infected with viruses. Some viruses are only pranks, and perform harmless actions like displaying a screen with a joke message on it. Others can destroy files or wipe out a hard drive. To avoid damage from viruses, write-protect the boot disk and other important disks, check new software or disks for viruses, and have virus protection software installed on the computer at all times. Disinfectant programs must be updated periodically because new viruses get into circulation over time. | |
| VLB | Vesa Local Bus | VESA standard for a uniform hardware interface, architecture, timing, electrical and physical specification of peripherals to a high-speed 32 bit, 130 Mbps bus, and compatibility among a wide variety of products. |
| VLC | Variable Length Code | Also known as Statistical compression. A data compression technique that uses the uneven probability distribution of the source symbols to shorten the average code length. Huffman code and arithmetic code belong to this group. By giving a short code to symbols occurring most often, the number of bits needed to represent the symbols decreases. |
| VOIP | Voice Over IP | Voice channels over the Internet usually with H.323 and IP protocols. Voice signals are digitised and split into packets and then sent over the Internet like any other data. |
| VPN | Virtual Private Network | A network which has the appearance and functionality of a dedicated line, but which is really like a private network within a public one, because it is still controlled by the telephone company, and its backbone trunks are used by all customers. |
| VPW | Variable Pulse Width | Class B Multiplexing - In the US, the SAE adopted J1850 as the standard protocol for Class B networks. J1850 was a joint effort among the Big Three (Ford, GM, Chrysler) and is actually a combination of GM's Class 2 protocol and Ford's SCP (Standard Corporate Protocol). The resulting standard has two basic versions. The first is a 10.4 Kb/s VPW (Variable Pulse Width) type which uses a single bus wire. The second is a 41.6 Kb/s PWM (Pulse Width Modulation) type which uses a two-wire differential bus. Chrysler adopted a variation of the 10.4Kb/s version. |
| VRM | Vehicle Radio Modem | Motorola device which receives data from computing equipment (usually into a serial communications channel) and transforms it into a form suitable for transmitting on an analog communications radio. Uses one or more of the standard protocols such as ARDIS and RD-LAP. |
| W is for ... | ||
| W3C | World Wide Web (=Wx3) Consortium | The W3C was founded in October 1994 to lead the World Wide Web to its full potential by developing common protocols that promote its evolution and ensure its interoperability. We are an international industry consortium, jointly hosted by the Massachusetts Institute of Technology Laboratory for Computer Science in the United States; the Institut National de Recherche en Informatique et en Automatique in Europe; and the Keio University Shonan Fujisawa Campus in Japan. Services provided by the Consortium include: a repository of information about the World Wide Web for developers and users; reference code implementations to embody and promote standards; and various prototype and sample applications to demonstrate use of new technology. Initially, the W3C was established in collaboration with CERN, where the Web originated, with support from DARPA and the European Commission. |
| WAI | Web Accessibility Initiative | The W3C's commitment to lead the Web to its full potential includes promoting a high degree of usability for people with disabilities. The Web Accessibility Initiative, in coordination with organizations around the world, is pursuing accessibility of the Web through five primary areas of work: technology, guidelines, tools, education & outreach, and research & development. |
| WAN | Wide Area Network | Data communications network that serves users across a broad geographic area and often uses transmission devices provided by common carriers. Frame Relay, SMDS, and X.25 are examples of WANs. See also LAN and MAN. |
| WAP | Wireless Application Protocol | The WAP Forum was founded by Ericsson, Motorola, Nokia and Unwired Planet in 1997. The purpose of WAP is to provide operators, infrastructure and terminal manufacturers, and content developers a common environment that will enable development of value-added services for mobile phones. The WAP protocol is targeted to bring advanced services and internet content to digital cellular phones and terminals. |
| WLL | Wireless Local Loop | A fixed service that competes with or substitutes for local wireline phone service. |
| WML | Wireless Markup Language | A tag-based display language providing navigational support, data input, hyperlinks, text and image presentation, and forms. A browsing langauge similar to Internet HTML. Part of the WAP protocol. |
| Word Macro Virus | An MS WORD MACRO Virus, is a macro (list of instructions) or template file (usually with the .DOT extension) which masquerades as legitimate MS WORD documents (usually with the extension *.DOC). An infected *.DOC file, doesn't look any different to the average PC user, as it can still contain a normal document. The difference is that this document is really just a template or macro file, with instructions to replicate, and possibly cause damage. MS WORD will interpret the *.DOT macro/template file regardless of extension, as a template file. This allows for it being passed off as a legitimate document (*.DOC) . These viruses commonly tend to infected the global macros, which get automatically saved at the end of each session. When the next session of MS WORD opens, the infected Global Macros are executed, and the WORD Environment is now infected, and will in turn be likely to infect documents whenever they are opened, closed, and created during all future sessions. | |
| Worm | A computer program that can make copies of itself, and spreads through connected systems, using up resources in affected computers or causing other damage. | |
| WWW | World-Wide Web | The World Wide Web is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. The World Wide Web is often abbreviated as the Web, WWW, or W3. The World Wide Web was developed in 1989 by Tim Berners-Lee of the European Particle Physics Lab (CERN) in Switzerland. The initial purpose of the Web was to use networked hypertext to facilitate communication among its members, who were located in several countries. Word was soon spread beyond CERN, and a rapid growth in the number of both developers and users ensued. In addition to hypertext, the Web began to incorporate graphics, video, and sound. Over the past few years, the use of the Web has reached global proportions. |
| WYSIWYG | What You See Is What You Get | Refers to text and graphics appearing on screen the same as they print. |
| X is for ... | ||
| X21 | ITU-T standard for serial communications over synchronous digital lines. The X.21 protocol is used primarily in Europe and Japan. | |
| X25 | X.25 is the CCITT's recommendation for the interface between a DTE and DCE over a Public Switched Telephone Network (PSTN). X.25 covers layers 1 to 3 of the ISO communication model. X.25 is carried within the Information Field of LAPB (Link Access Protocol, Balanced) frames. | |
| xDSL | General term for high speed data methods over a single twisted copper pair. See ADSL, HDSL, SDSL and VDSL above. | |
| XGA | Sometimes used instead of XVGA (see below) | |
| XML | eXtensible Markup Language | XML is subset of the Standard Generalized Markup Language (SGML) defined in ISO standard 8879:1986 that is designed to make it easy to interchange structured documents over the Internet. XML files always clearly mark where the start and end of each of the logical parts (called elements) of an interchanged document occurs. XML restricts the use of SGML constructs to ensure that fall back options are available when access to certain components of the document is not currently possible over the Internet. It also defines how Internet Uniform Resource Locators can be used to identify component parts of XML data streams. |
| XNS | Xerox Network Systems | Protocol suite originally designed by PARC. Many PC networking companies, such as 3Com, Banyan, Novell, and UB Networks used or currently use a variation of XNS as their primary transport protocol. |
| XON/XOF | With the DCE speed typically lower than the DTE speed, and often the two DTE speeds being different, we need a way to make the data start and stop at the right moment: Flow Control. The standard technique of flow control, left over from the old and slow days of the teletype, uses what is called the Xon/Xoff protocol. Both Xon and Xoff are normal ASCII characters; Control-Q, ASCII value 17, is Xon. This is read as: Start Sending, I am ready! Control-S, ASCII value 19, is Xoff. It is seen as: Stop Sending! I cannot read anymore! So with Xon/Xoff flow control, a computer will start sending information to a modem. If DCE and DTE speed are equal and there is no compression, it will simply pass all data on to the other end. It will get the data, and send it to the computer, who should have the same DTE and DCE speed. The computer will process the data, and everything will work fine. If the receiving computer needs a moment to do something it simply sends an Xoff character down the line. The sending computer will get it and stop sending, waiting for an Xon so it can start sending again. The same happens the other way around. | |
| XVGA | eXtended Video Graphics Array | VESA standard for high resolution displays, usually 1024 X 768 pixels. |
| Y is for ... | ||
| YMMV | Your Mileage May Vary | i.e, don't blame me if you get slightly different results on a different system. Usenet/Chat acronym/abbreviation |
| Z is for ... | ||
Thanks also to Avi Tooba for some terms and to the following (highly recommended) sources that I used to check some definitions:
Comments, need more help or information ?
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