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Computer, Telephony & Electronics
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1. In telephony insiders jargon, an abbreviation for carrier.
2. The most commonly used programming variable, usually used on loop routines.
3. A programmer's previous position, as opposed to a previous spouse.
4. The measure of speed on a CD-ROM or DVD.
5. A designated abbreviation in communications to signify cross connections such as the opposite connection from conventional. For instance, on an Ethernet cable used with a hub, pins 1, 2, 3 and 6 are used and go to the same number on the other end of the cable. However, an Ethernet X cable has pins 1 and 2 going to pins 5 and 6 on the other end, and pins 5 and 6 go to pins 1 and 2.
6. The electronic symbol for reactance.
This is a popular line of electronic, centrally controlled devices. It was originally designed by BSR in the early 1970s, a full generation before it became popular. BSR has since licensed the technology to several other companies. The product ownership rights are now owned by X10 Wireless Technologies, Incoporated. Devices include switches, dimmers, thermostats, garage door openers, outlets, timers and other electrical mechanisms. All can be controlled by a standard ASCII coded controller or by a computer interfaced to such a controller. See the various X10 technologies at HTTP://WWW.X10.COM.
One of the most popular implementations of the UNIX X-Window system. X11 is supported by the Open Group X Project team.
The ITU-T standard specification describing an addressing scheme used in X.25 networks. X.121 addresses are sometimes called IDNs.
A technology developed by U.S. Robotics (now 3COM) for delivering data rates up to 56 Kbps over plain old telephone service (POTS). It was long believed that the maximum data transmission rate over copper telephone wires was 33.6 Kbps, but X2 achieves higher rates by taking advantage of the fact that most phone switching stations are connected by high-speed digital lines. X2 bypasses the normal digital-to-analog conversion and sends the digital data over the telephone wires directly to your modem where it is decoded. 3COM has announced that future X2 modems will conform to the new V.90 standard approved by the ITU. And users with older X2 modems may upgrade their modems to support V.90. While X2 offers faster Internet access than normal modems, there are several caveats to using an X2 modem:
1. The high speeds (roughly 53Kbps) are available only with downstream traffic (e.g., data sent to your computer). Upstream traffic is delivered using normal techniques, with a maximum speed of 33.6 Kbps.
2. To connect to the Internet at X2 speeds, your Internet Service Provider (ISP) must have a modem at the other end that is also X2 or supports V.90.
3. Five X2s do not make one X10.
4. Even if your ISP supports has X2 or V.90, you might not achieve maximum transmission rates due to noisy lines or other limiting factors, a common characteristic of X2. Take a look at 3COM on the web at HTTP://WWW.3COM.COM.
X.25 is the most popular packet-switching protocol for LANs. Ethernet, for example, is based on the X.25 standard. The X.25 standard was approved by the CCITT (now the ITU) in 1976. It defines layers 1, 2, and 3 in the OSI Reference Model. The current ITU-T standard that defines how connections between DTE and DCE are maintained for remote terminal access and computer communications in PDNs. X.25 now specifies LAPB, a data link layer protocol, and PLP, a network layer protocol. Frame Relay has to some degree superseded X.25.
This ITU-T recommendation that defines the terminal to PAD interface in X.25 networks.
This ITU-T recommendation that defines the form for control information in the terminal to PAD interface used in X.25 networks.
X.400 is the universal protocol for E-Mail. X.400 defines the envelope for E-Mail messages so all messages conform to a standard format. It is an ISO and ITU standard for addressing and transporting E-Mail messages. It conforms to layer 7 of the OSI model and supports several types of transport mechanisms, including Ethernet, X.25, TCP/IP, and standard telephone dial-up lines.
X.500 is an ISO and ITU extension to the X.400 standard that defines addressing formats so all E-Mail systems can be linked together, including how global directories should be structured. X.500 directories are hierarchical with different levels for each category of information, such as country, state, and city. X.500 totally supports X.400 systems.
X.75 is the ITU-T specification that defines the signaling system between two PDNs. X.75 is essentially an NNY.
1. An industry abbreviation for the line of microprocessors from Intel, beginning with the 8086. The abbreviation was usually used to indicate compatibility with the entire line including 80286, 80386 and 80486; often it included the original Pentium which was dubbed the 80586 by the industry but not by Intel. Many competitors of the Intel line called the CPUs they made '586 and '686 compatible, though Intel never made either.
2. Any computer based on an 8086, 80286, 80386, 80486, or Pentium microprocessor, or instruction compatible processor.
An abbreviation for eXtended Architecture (XA). An extension to IBM's System/370 mainframe architecture that takes advantage of continuing high performance enhancements to computer system hardware.
One of two coordinates to give an exact point. The other is Y coordinate. Together they are termed X,Y coordinates. A third, though less common, is for a third dimension, the Z coordinate.
X D Picture Card or x D
This is a type of technology, formally known as x D Picture Card, for mass storage devices in the form of a new type of memory media with an ultra-compact design about the size of a postage stamp, image storage capacity of up to 8 gigabytes, compatibility with different digital camera brands, and prices that are comparable to current SmartMedia cards. Fuji and Olympus cameras are the designers and manufacturers of this technology. As of 1/1/2004, the card sizes are 16MB, 32MB, 64MB, 128MB, 256MB and 512MB. Larger storage is in process. For those using CF readers presently, adaptors are available. x D is part of a generic category of media called Digital Flash Media (DFM).
The xDSL designation refers collectively to all types of digital subscriber lines, the two main categories being ADSL and SDSL. Two other types of xDSL technologies are High-data-rate DSL (HDSL) and Single-line DSL (SDSL). DSL technologies use sophisticated modulation schemes to pack data onto copper wires. They are sometimes referred to as last-mile (see local loop) technologies because they are used only for connections from a telephone switching station to a home or office, not between switching stations. xDSL is similar to some types of ISDN inasmuch as both operate over existing copper telephone lines (POTS) and both require the short runs to a CO (central telephone office). As a rule, that run distance usually must be less than 20,000 feet. However, xDSL offers much higher speeds, up to 32 Mbps for downstream traffic, and from 32 Kbps to over 1 Mbps for upstream traffic. See SDSL, HDSL, ADSL, SLDSL and DSL.
An operating system that is in the 'NIX family. A version of UNIX that runs on PCs. Xenix was developed by Microsoft Corporation, for IBM (imagine that!), and is compatible with AT&T's System V definition. IBM currently owns the rights to Xenix but has shipped some servers with Linux on them. Demand was quite good in the early 90's but has dwindled, much like OS2.
The formal name for a line of Pentium II chipsets from Intel, originally introduced in 1998. Unlike all previous Pentium II chips, which used a Slot 1 form factor, Xeon chips used Slot 2. This allowed for considerably faster data transfers between the CPU and L2 cache. The original Xeon chip speeds start at 400 Mhz. This technology was originally designed for use on servers and other dedicated computers passing data from one location to another. The technology, in modified version, has since become part of the Pentium III line with speeds of 1100+ Mhz. It was modified in the P4 line so that multiple processors were the goal of this technology, both on servers and stations. As of July, 2003, the processor speed is 3Ghz. Check Intel out on the web at HTTP://WWW.INTEL.COM. They have a spectacular site and much information.
Xerox Corporation, a leader in today's office technology, particularly copiers. Though, not often associated with computer technology, they are generally regarded as the initial force in graphical presentation and desktop publishing. Those two factors in the computer industry eventually led to the current Internet technology of today. Check them out on the web at HTTP://WWW.XEROX.COM. XEROX tends to get into and out of the computer industry every couple of years. This depends on view point of different people in management as to how computers relate to office structure and work possibilities.
The acronym for eXtended Graphics Array, a high-resolution graphics standard introduced by IBM in 1990. XGA was designed to replace the older 8514/A video standard. It provides the same resolutions (640 by 480 or 1024 by 768 pixels), but supports more simultaneous colors (65 thousand compared to 8514/A's 256 colors). In addition, XGA allows monitors to be non-interlaced.
A play on radio terminology AM and FM, and a step toward tomorrow as far as unmatched entertainment.
on September 25, 2001. A spectacular technology of satellite radio; it is a paid service, however, well worth the small charge in our opinion, costing less than the competing technology, Sirius. (Please see our commentary as to why this is NOT a link to Sirius...) Each unit has an identity module that is registered with the service, once activated, it is usable 24 hours a day, anywhere in the country, perhaps on the continent. They offer 160 channels or more of music, news, events and entertainment.
As of February 19, 2007, XM Radio announced that they are merging with Sirius to form a larger better satellite entertainment operation. We will keep you informed on that as it progresses. Where today, our exclusive contracts with either company mean we must choose between baseball and football or Oprah and Martha Stewart. The new digital media company will seek to ensure that in the future, you, the listener paying the bills, will be able to access both companies' programming. And, once fully integrated, those of you who have factory-installed satellite radio in your vehicles (as we do - XM - in our Chevy service trucks) will no longer be limited to the programming provided by the exclusive satellite radio service chosen by their car manufacturer. Those of us with after market installations in the vehicles or in other installations, home, business, boats and planes, will also see the advantages. According to XM CEO, Hugh Panero, this merger should be completed in late 2007 or early in 2008. This sounds like a win-win situation to us... that is if pricing does not increase and if Howard Stern is no longer involved.
Based in Washington, DC, XM's broadcast signal is uplinked via two huge land station antennae (about 7 meters across) to each of the two (as of February 28, 2005, three) Boeing Satellite Systems manufactured model 702 satellites. Internationally identified as XM-1, launched May 8, 2001, XM-2, launched on March 18, 2001, and XM-3, launched February 28, 2005 (a picture of the launch). All were sea based commercial launches by Sea Launch Company based in Long Beach, CA, for the 15 to 18KW (kilowatts), solar wing powered, broadcast satellites known affectionately as "Rock", "Roll" and "Rhythm", though Roll, XM-1 (a picture of the launch), was launched after XM-2 (pictures of the launch). Each, in orbit, is about 133 feet long by 47 feet wide and weighs about 10,346 pounds, give or take a few ounces. These satellites don't move in relationship to the Earth (get information in relationship to you); positioned more than 22,000 miles above the earth in geostationary orbit (Rock was an orbit above the West over the Southern area of the Colorado river but is being re-positioned in the Eastern area and Rhythm (XM-3) is now at 85.0 degrees west longitude at an altitude of 22242 nautical miles, where Rock used to be, and Roll is at 115.0 degrees west Longitude at an altitude of 22244 NM.), their beams combine to span the entire contiguous country and beyond. Ground antennae and land based repeaters keep the signal strong in difficult areas that might have problems with line of sight from the satellites. There are receiver units for home, vehicles and portable use that offer magnificent sound quality with limited or no commercial interruption on frequencies between 2,332.50 and 2,345.00 MHz in the S band (current S Band users here). Check this new innovation out on the web at HTTP://WWW.XMRADIO.COM for more details and programming information. See Phlash.
XM has partnerships with GM, Honda, and other auto manufacturers, with leading audio manufacturers such as Delphi, Pioneer, Alpine and Sony, and with electronics retailers such as Walmart, Best Buy, Circuit City, Sears and participating Radio Shack franchise dealers, that favorably position XM Radio within the reach of millions of consumers. The main broadcast facility is in the home offices in Washington DC; however, XM also has broadcast facilities in New York and Nashville, and additional offices in Boca Raton, FL; Southfield, MI; and Yokohama, Japan.
XMI is an acronym for XML Metadata Interchange. XMI is a proposed use of the Extensible Markup Language (XML) that is intended to provide a standard way for programmers and other users to exchange information about metadata (essentially, information about what a set of data consists of and how it is organized). Specifically, XMI is intended to help programmers using the Unified Modeling Language (UML) with different languages and development tools to exchange their data models with each other. In addition, XMI can also be used to exchange information about data warehouses. Effectively, the XMI format standardizes how any set of metadata is described and requires users across many industries and operating environments to see data the same way. XMI is a proposal from the Object Management Group (OMG) that builds on and extends these industry standards or recommendations:
1. Extensible Markup Language (XML), a standard from the World Wide Web Consortium (W3C)
2. Unified Modeling Language (UML), a standard from OMG
3. Meta Object Facility (MOF), another standard from the OMG for a metamodeling and metadata repository
Ideally, XMI will allow different cooperating companies a way to use each other's data repositories. XMI is described as similar to, yet competing with, Microsoft's Open Information Model. Our money is on Microsoft.
An acronym for Extensible Markup Language. XML is a flexible way to create common information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere. For example, computer makers might agree on a standard or common way to describe the information about a computer product (processor speed, memory size, and so forth) and then describe the product information format with XML. Such a standard way of describing data would enable a user to send an intelligent agent (a program) to each computer maker's Web site, gather data, and then make a valid comparison. XML can be used by any individual or group of individuals or companies that wants to share information in a consistent way. Currently a formal recommendation from the World Wide Web Consortium (W3C). XML is similar to the language of today's Web pages, HTML. Both XML and HTML contain markup symbols to describe the contents of a page or file. HTML, however, describes the content of a Web page (mainly text and graphic images) only in terms of how it is to be displayed and interacted with. For example, a <P> starts a new paragraph. XML describes the content in terms of what data is being described. For example, a could indicate that the data that followed it was a phone number. This means that an XML file can be processed purely as data by a program or it can be stored with similar data on another computer or, like an HTML file, that it can be displayed. For example, <PHONENUM> depending on how the application in the receiving computer wanted to handle the phone number, it could be stored, displayed, or dialed.
One of the earliest reliable file transfer protocols, X-Modem was written in 1977 by Ward Christiansen (one of the early "good guys" of the industry as far as communications) for use on the first BBS. This protocol used 128 byte blocks for data and a simple checksum for error detection. The process was effective but slow. A later version was called X-Modem2 and used a CRC error detection method. A third version called X-Modem1K used 1024 byte blocks and CRC but was never popular due to the fact Z-Modem was already popularly in use and was no slower but had a better error detection scheme. It did however, use only 512 byte blocks by comparison. Contrary to popular belief, X-Modem has nothing to do with X-Men. See also Y-Modem and Z-Modem.
An acronym for Xerox Network Systems (XNS). The suite of internet protocols developed by the Xerox Corporation; generally used by larger systems using IBM operating systems. Although similar to TCP/IP protocols, XNS uses different packet formats and terminology.
A front page service and information service available to the general public, not unlike Excite, AltaVista and similar portal services. Check Xoom services out on the web at HTTP://WWW.XOOM.COM.
Xon/Xoff is a protocol for controlling the flow of data between computers (DCE) and other devices (DTE) on an asynchronous serial connection. For example, a computer typically sends data to a printer faster than the printer can print. The printer contains a buffer where data is stored until the printer catches up with the computer. If the buffer becomes full before the printer catches up, a small microprocessor in the printer sends back an Xoff signal to stop sending data. When enough data is printed and buffer storage becomes free, the printer sends an Xon signal telling the computer to resume sending data. The "X" stands for "transmitter" so the Xon and Xoff are signals to turn a transmitter on or off. The actual signal for Xon is the same bit configuration as the ASCII Ctrl-Q keyboard combination. The Xoff signal is the Ctrl-S character. The normal technology of the day was serial communications through a 25 pin connector. The minimum needed for normal data communication and handshake was pin 2 to pin 3 of the opposite connector, pin 3 to pin 2 of the opposite connector, pin 7 to pin 7 and pin 20 to pin 20. Pins 2 and 3 were send and receive data, pin 7 was signal ground and pin 20 was handshake. Xon/Xoff being in the data flow, did not require pin 20. It was, as were all serial communications of the time, often misunderstood in testing for the characters. Often it was combined with other handshakes for better detection. When you define your modem to your computer's operating system, you may need to specify the use of flow control with Xon/Xoff or with CTS/RTS (Clear to Send/Ready to Send) or both. When sending binary data, Xon/Xoff may not be recognized because it is character-encoded.
Characterized and recognized as the exclusive OR operator, a Boolean operator that returns a value of TRUE only if just one of its operands is TRUE. In contrast, an inclusive OR operator returns a value of TRUE if either or both of its operands are TRUE.
An acronym for X.25 over TCP/IP.
Microsoft's newest graphical operating system, an alternative to Windows 95, Windows 98, Windows NT, Windows 2000 and Windows ME and more a true multi-user multi-tasking operating system, based on NT and 2000 technology. It is touted by Microsoft as the operating system of the future and state that it is not crashable; I beg to differ. There is only a workstation client version at present but it comes in both home and professional designations with some obvious business features removed from the home version. Since XP is a preemptive 32 bit OS that is NOT backward compatible to DOS entirely, it is also more easily ported to other types of processors, such as RISC and Motorola, instead of only Intel and Intel look alikes. Microsoft plans to take advantage of that. There have been major security issues in the first three months since the release of XP, though it was supposed to be the most secure OS ever, according to Microsoft. SP1 is out and available.
XPath is a language that describes a way to locate and process items in Extensible Markup Language (XML) documents by using an addressing syntax based on a path through the document's logical structure or hierarchy. The original purpose of this standards was for a uniform mapping language for geological databases and devices needing access to them. That, as most attempts to standardization in the industry, has not happened yet. to any extent, this effort in itself makes writing programming expressions easier than if each expression had to understand typical XML markup and its sequence in a document. XPath also allows the programmer to deal with the document at a higher level of abstraction. XPath is a language that is used by and specified as part of both the Extensible Stylesheet Language Transformations (XSLT) and by XPointer (SML Pointer Language). It uses the information abstraction defined in the XML Information Set (Infoset). Since XPath does not use XML syntax itself, it could be used in contexts other than those of XML. XPath uses a syntax something like an informal set of directions for finding a particular geographic location. When telling someone how to find the Eastern Point of our city limits in Palm Springs, CA, for example, you might write:
which would put the user at the flood basin bridge on Ramon Road, the eastern edge of Palm Springs, the city limits of Palm Springs and Catherdral City. The key difference between XPath and earlier languages is that XPath specifies a route, rather than pointing to a specific set or sequence of characters, words, or other elements. XPath uses the concepts of the concept node (the point from which the path address begins), the logical tree that is inherent in any XML document, and the concepts expressing logical relationships that are defined in the XML Information Set, such as ancestor, attribute, child, parent, and self. XPath includes a small set of expressions for specifying mathematics functions and the ability to be extended with other functions.
A telephony slang abbreviation for Carrier Private Line.
XQL is an acronym for XML Query Language. XQL is a way to locate and filter the elements (data fields) and text in an Extensible Markup Language (XML) document. XML files are used to transmit collections of data between computers on the Web. XQL provides a tool for finding and/or selecting out specific items in the data collection in an XML file or set of files. It is based on the pattern syntax used in the Extensible Stylesheet Language (XSL) and is proposed as an extension to it. The XSL pattern language is a declarative way to indicate specific elements for processing. It uses simple directory notation. For example, book/author means: Select all author elements in all book elements in a particular context (for example, within an XML file or a set of files). XQL adds to this directory pattern notation the ability to use Boolean logic, to filter out elements, to index into a collection of elements, and to do some other things. Using XQL, a program could be written to search repositories of XML files, to provide hypertext links to specific elements, and for other applications.
A telephony slang abbreviation for Carrier Switched.
An X-Server is a server of connections to X-Terminals in a distributed network environment that uses the X-Window System. From the terminal user's point-of-view, the X-Server may seem like a server of applications in multiple windows. Actually, the applications in the remote computer with the X-Server are making client requests for the services of a windows manager that runs in each terminal. X-Servers (as part of the X-Window System) typically are installed in a UNIX-based operating system in a mainframe, minicomputer, or workstation. The X-Server may be compared to Microsoft's Terminal Server except that the latter is running on a Windows-based operating system. However, there are X-Servers designed to run on a Microsoft Windows-based operating system.
An acronym for eXensible Style Language. A specification for separating style from content when creating HTML or XML pages. The specifications work much like templates, allowing designers to apply single style documents to multiple pages. XSL is the second style specification to be offered by the World Wide Web Consortium (W3C). The first, called Cascading Style Sheets (CSS), is similar to XSL but does not include two major XSL's innovations, allowing developers to dictate the way Web pages are printed, and specifications allowing one to transfer XML documents across different applications. W3C released the first draft of XSL in August 1998, and promotes the specifications as helpful to the Web's speed, accessibility, and maintenance.
An acronym for eXensible Style Language Translation. XSLT is a standard way to describe how to transform (change) the structure of an XML (Extensible Markup Language) document into an XML document with a different structure. XSLT is a Recommendation of the World Wide Web Consortium (W3C). XSLT can be thought of as an extension of the Extensible Stylesheet Language (XSL). XSL is a language for formatting an XML document (for example, showing how the data described in the XML document should be presented in a Web page). XSLT shows how the XML document should be reorganized into another data structure (which could then be presented by following an XSL style sheet). XSLT is used to describe how to transform the source tree or data structure of an XML document into the result tree for a new XML document, which can be completely different in structure. The coding for the XSLT is also referred to as a style sheet and can be combined with an XSL style sheet or be used independently.
An X-Terminal is typically a diskless terminal (or station emulating a terminal) especially designed to provide a low cost user interface for applications that run in a network X-Server environment as part of a distributed X-Window System. Typically, X-Terminals are connected to a server running a UNIX-based operating system in a mainframe, minicomputer, or workstation. X-Terminals (and the X-Window System) appear to have been the forerunner for what is now generally called "network computers" or thin clients. The X-Window System and X-Terminals continue to offer an alternative to Microsoft's Terminal Server and their Net PC.
A network-based GUI designed for Unix systems, there are thousands of free applications available as source code and compiled executables for X-Window compatible systems, including PC-based X-terminal emulators. X-Windowing systems are interesting in that they reverse the usual client-server metaphor. See X11.
The term x, y coordinates designates intersection points. In particular, they are respectively the horizontal and vertical addresses of any pixel or addressable point on a computer display screen. The x coordinate is a given number of pixels along the horizontal axis of a display starting from the pixel (pixel 0) on the extreme left of the screen. The y coordinate is a given number of pixels along the vertical axis of a display starting from the pixel (pixel 0) at the top of the screen. Together, the x and y coordinates locate any specific pixel location on the screen. x and y coordinates can also be specified as values relative to any starting point on the screen or any subset of the screen such as an image. On the Web, each clickable area of an imagemap is specified as a pair of x and y coordinates relative to the upper left-hand corner of the image.
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