Ultra wideband (also known as UWB or as digital pulse wireless) is a wireless technology for transmitting large amounts of digital data over a wide spectrum of frequency bands with very low power for a short distance. Ultra wideband radio not only can carry a huge amount of data over a distance up to 230 feet at very low power (less than 0.5 milliwatts), but has the ability to carry signals through doors and other obstacles that tend to reflect signals at more limited bandwidths and a higher power. Ultra wideband can be compared with another short-distance wireless technology, Bluetooth, which is a standard for connecting handheld wireless devices with other similar devices and with desktop computers.
Ultra wideband broadcasts digital pulses that are timed very precisely on a carrier signal across a very wide spectrum (number of frequency channels) at the same time. Transmitter and receiver must be coordinated to send and receive pulses with an accuracy of trillionths of a second. On any given frequency band that may already be in use, the ultra wideband signal has less power than the normal and anticipated background noise so theoretically no interference is possible. Time Domain, a company applying to use the technology, uses a microchip manufactured by IBM to transmit 1.25 million bits per second, but says there is the potential for a data rate in the billions of bits per second.
Ultra wideband has two main types of application:
1) Applications involving radar, in which the signal penetrates nearby surfaces but reflects surfaces that are farther away, allowing objects to be detected behind walls or other coverings.
2) Voice and data transmission using digital pulses, allowing a very low powered and relatively low cost signal to carry information at very high rates within a restricted range.
In the U.S., the Federal Communications Commission approved the commercial use of ultra wideband on February 14, 2002.
UNC - Universal Naming Convention:
See Universal Naming Convention.
Unicode is an entirely new idea in setting up binary codes for text or script characters. Officially called the Unicode Worldwide Character Standard, it is a system for "the interchange, processing, and display of the written texts of the diverse languages of the modern world." It also supports many classical and historical texts in a number of languages.
Currently, the Unicode standard contains 34,168 distinct coded characters derived from 24 supported language scripts. These characters cover the principal written languages of the world.
Additional work is underway to add the few modern languages not yet included.
Also see the currently most prevalent script or text codes, ASCII and extended binary-coded decimal interchange code (EBCDIC).
Uniform Resource Locator - URL:
A URL (Uniform Resource Locator) (pronounced YU-AHR-EHL or, in some quarters, UHRL) is the address of a file (resource) accessible on the Internet. The type of resource depends on the Internet application protocol. Using the World Wide Web's protocol, the Hypertext Transfer Protocol (HTTP) , the resource can be an HTML page (like the one you're reading), an image file, a program such as a common gateway interface application or Java applet, or any other file supported by HTTP. The URL contains the name of the protocol required to access the resource, a domain name that identifies a specific computer on the Internet, and a hierarchical description of a file location on the computer.
On the Web (which uses the Hypertext Transfer Protocol), an example of a URL is:
which describes a Web page to be accessed with an HTTP (Web browser) application that is located on a computer named www.mhrcc.org. The specific file is in the directory named /kingston and is the default page in that directory (which, on this computer, happens to be named index.html).
An HTTP URL can be for any Web page, not just a home page, or any individual file.
A URL for a program such as a forms-handling common gateway interface script written in Perl might look like this:
A URL for a file meant to be downloaded would require that the "ftp" protocol be specified like this one:
A URL is a type of URI (Uniform Resource Identifier).
Universal Naming Convention - UNC:
In a network, the Universal Naming Convention (UNC) is a way to identify a shared file in a computer without having to specify (or know) the storage device it is on. In Windows operating systems, Novell NetWare, and possibly other operating systems, the UNC can be used instead of the local naming system (such as the DOS naming system in Windows).
In Windows operating systems, the UNC name format is:
The share name is sometimes said to logically identify the volume or storage device that the file is on, but the idea is to free the user from having to know this. The path is zero or more folder or subfolder names (in other words, the file name may exist directly under the sharename). For example:
might specify on a server in the corporate main office a shared file (patentap.html) kept with other legal forms that members of a corporation's legal department might download and read or print and use. Printers and other devices can also be addressed using UNC.
Universal Unique Identifier - UUID:
A UUID (Universal Unique Identifier) is a 128-bit number used to uniquely identify some object or entity on the Internet. Depending on the specific mechanisms used, a UUID is either guaranteed to be different or is, at least, extremely likely to be different from any other UUID generated until 3400 A.D. The UUID relies upon a combination of components to ensure uniqueness. A guaranteed UUID contains a reference to the network address of the host that generated the UUID, a timestamp (a record of the precise time of a transaction), and a randomly generated component. Because the network address identifies a unique computer, and the timestamp is unique for each UUID generated from a particular host, those two components should sufficiently ensure uniqueness. However, the randomly generated element of the UUID is added as a protection against any unforseeable problem.
A UUID is specified as part of the tModel data structure, which represents a service type (a generic representation of a registered service) in the UDDI (Universal Description, Discovery, and Integration) registry. This mechanism is used to discover Web services.
UUIDs could be generated to refer to almost anything imaginable. Microsoft and some other software companies refer to GUIDs (global unique identifiers), a type of UUID used to refer to Component Object Module objects and other software components. The first UUIDs were created in the Network Computing System (NCS), and subsequently became a component of the Distributed Computing Environment (DCE) of the Open Software Foundation (OSF).
UNIX (often spelled "Unix" in news media) is an operating system that originated at Bell Labs in 1969 as an interactive time-sharing system. Ken Thompson and Dennis Ritchie are considered the inventors of UNIX. The name (pronounced YEW-nihks) was a pun based on an earlier system, Multics. In 1974, UNIX became the first operating system written in the C language. UNIX has evolved as a kind of large freeware product, with many extensions and new ideas provided in a variety of versions of UNIX by different companies, universities, and individuals.
Partly because it was not a proprietary operating system owned by any one of the leading computer companies and partly because it is written in a standard language and embraced many popular ideas, UNIX became the first open or standard operating system that could be improved or enhanced by anyone. A composite of the C language and shell (user command) interfaces from different versions of UNIX were standardized under the auspices of the IEEE as the Portable Operating System Interface (POSIX). In turn, the POSIX interfaces were specified in the X/Open Programming Guide 4.2 (also known as the "Single UNIX Specification" and "UNIX 95"). Version 2 of the Single UNIX Specification is also known as UNIX 98. The "official" trademarked UNIX is now owned by the The Open Group, an industry standards organization, which certifies and brands UNIX implementations.
UNIX operating systems are used in widely-sold workstation products from Sun Microsystems, Silicon Graphics, IBM, and a number of other companies. The UNIX environment and the client/server program model were important elements in the development of the Internet and the reshaping of computing as centered in networks rather than in individual computers. Linux, a UNIX derivative available in both "free software" and commercial versions, is increasing in popularity as an alternative to proprietary operating systems.
Unshielded Twisted Pair - UTP:
This definition closely duplicates the definition for twisted pair.
Unshielded twisted pair is the most common kind of copper telephone wiring. Twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. To reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. Each signal on twisted pair requires both wires. Since some telephone sets or desktop locations require multiple connections, twisted pair is sometimes installed in two or more pairs, all within a single cable. For some business locations, twisted pair is enclosed in a shield that functions as a ground. This is known as shielded twisted pair (STP).
Twisted pair is now frequently installed with two pairs to the home, with the extra pair making it possible for you to add another line (perhaps for modem use) when you need it.
Twisted pair comes with each pair uniquely color coded when it is packaged in multiple pairs. Different uses such as analog, digital, and Ethernet require different pair multiples.
Although twisted pair is often associated with home use, a higher grade of twisted pair is often used for horizontal wiring in LAN installations because it is less expensive than coaxial cable.
The wire you buy at a local hardware store for extensions from your phone or computer modem to a wall jack is not twisted pair. It is a side-by-side wire known as silver satin. The wall jack can have as many five kinds of hole arrangements or pinouts, depending on the kinds of wire the installation expects will be plugged in (for example, digital, analog, or LAN) . (That's why you may sometimes find when you carry your notebook computer to another location that the wall jack connections won't match your plug.)
URL - Uniform Resource Locator:
See Uniform Resource Locator.
UTC - Coordinated Universal Time:
Coordinated Universal Time (abbreviated as UTC, and therefore often spelled out as Universal Time Coordinated and sometimes as Universal Coordinated Time) is the standard time common to every place in the world. Formerly and still widely called Greenwich Mean Time (GMT) and also World Time, UTC nominally reflects the mean solar time along the Earth's prime meridian. (The prime meridian is 0° longitude in the 360 lines of longitude on Earth. There are 179 meridians toward the East and 179 toward the West. The 180th meridian is also called the International Date Line.) The prime meridian is arbitrarily based on the meridian that runs through the Greenwich Observatory outside of London, where the present system originated. The UTC is based on an atomic clock to which adjustments of a second (called a leap second) are sometimes made to allow for variations in the solar cycle.
Coordinated Universal Time is expressed using a 24-hour clock but can be converted into a 12-hour clock (AM and PM). UTC is used in plane and ship navigation, where it also sometimes known as Zulu. UTC uses the Gregorian calendar calendar.
UTC was defined by the International Radio Consultative Committee (CCIR), a predecessor organization of the ITU-TS, and is maintained by the Bureau International des Poids et Mesures (BIPM).