W

W Band - The band of frequencies designated by the IEEE between 75 GHz and 110 GHz. For a table, see IEEE Radar Band Designation.

W-CDMA (Wideband Code Division Multiple Access) - Also known as Universal Mobile Telecommunications System (UMTS). See UMTS.

W - Symbol for watt. See watt.

w³ (WWW, or World Wide Web) - See WWW.

W3C (World Wide Web Consortium - An international partnership of companies that are involved with Internet and the World Wide Web that was founded in 1994 by Tim Berners-Lee. The purpose of W3C is to oversee the development of open standards to evolve the Web in a uniform manner that is usable by everyone and to prevent competing factions from implementing proprietary browser formats. The W3C is the chief standards organization for HTTP (Hypertext Transfer Protocol) and HTML (Hypertext Markup Language).

WACS (Wireless Access Communication System) - A U.S. specification for cordless telephony that was modified to an industry standard known as Personal Access Communications Services (PACS) and ultimately evolved into Personal Communications Services (PCS). See also cordless telephone and PCS.

Waffle Splice Closure - A cable splice closure that is commonly used in air-pressure applications or shallow trenches, where a strong casing is needed to protect the splice. See also Air Pressure.

WAIS (Wide Area Information Service) - A UNIX-based system of servers that enables users to specify the databases requested for search, and to conduct a subject-matter search on the basis of keywords. See also browser, server, and UNIX.

Walkabout - An early wireless telephony trial conducted in Canberra,Australia, in support of pedestrian traffic.Walkabout was based on CT2+ digital cordless telephony standards. See also cordless telephone,CT2+, and digital.

walkie talkie - A portable handheld radio transmitter-receiver invented in 1938 by Al Gross while a high school student in Cleveland, Ohio (United States).The device caught the attention of the Office of Strategic Services (OSS), predecessor to the Central Intelligence Agency (CIA).The OSS recruited Goss, who then lead the effort to develop the walkie-talkie for clandestine and military uses. Code-named Joan/Eleanor, the first walkie talkie system comprised a ground unit, Joan, and an airborne unit, Eleanor. The system allowed OSS agents behind enemy lines to communicate with aircraft in a manner that virtually defied detection at the time. See also Gross,Al.

WAN (Wide-Area Network) - A network of computers or computing devices connected by telephone lines that extend beyond an area code’s service area. An example of a WAN application is a computer that accesses another computer in another state to access information. Popular ways for computers to connect over long distances are by using a dial-up modem, a frame relay circuit, an ATM circuit, an ISDN circuit, or a 56K leased line. There are advantages and disadvantages to each of these services (which are offered by long-distance telephone companies). The faster and more reliable the service, the more expensive it is. Frame relay is rapidly becoming the most economical WAN protocol for applications that transfer data over long distances frequently

WAN Interface Sublayer (WIS) - See WIS.

WAP (Wireless Access Protocol) - A carrier-independent, device-independent, transaction-oriented protocol employed in Web-enabled cellular networks in support of text, graphics, and audio.The best performance is achieved when accessing Web sites written in WML (Wireless Markup Language), which is similar to HTML.The alternative is transcoding from HTML to WML, which is accomplished through gateways.A much simpler, but much less attractive technique is Web clipping, which strips the graphic content out of Web pages. Security over the wireless link is provided through Wireless Transport Layer Security (WTLS).WAP is employed outside of Japan, where the i-Mode microbrowser technology is employed. See also browser, carrier, cellular, i-Mode, protocol, We b, and WML.

WARC (World Administrative Radio Conferences) - Now known as the World Radio Conferences (WRC). See WRC.

warrior’s code - A code of conduct that defines what warriors can and cannot do if they wish to continue to be regarded as warriors, rather than murderers or cowards. For the warrior who adheres to such an informal code or to more formal rules of engagement, certain actions are unthinkable, even in the most dire or extreme circumstances.Within a decade of the introduction of firearms to Japan in 1543, the Japanese were arguably the best gun makers in the world, and there were more guns per capita in Japan than in any other country in the world.The warrior code of the Samurai, however, viewed the use of guns in warfare as dishonorable. Centuries of tradition demanded that Samurai warriors engage in elaborate rituals prior to combat, which was conducted man-to-man and hand-to-hand between gentleman warriors. Under pressure from the Samurai, the Emperor of Japan gradually reduced the number of authorized gun factories to zero and, over time, subsequently reduced the number of gun repair shops to zero. By the time that Commodore Perry visited in the 1840s, there was not a single gun left in Japan, which left the Japanese at a decided disadvantage against the superior weaponry of the Europeans. See also Geneva Convention and rules of engagement.

Watchdog Timer - 1. A hardware or software mechanism that is used to trigger an event or an escape from a process unless the timer is periodically reset. 2. In NetWare, a timer that indicates the maximum period of time that a server will wait for a client to respond to a watchdog packet. If the timer expires, the server sends another watchdog packet (up to a set maximum).

water peak - A peak in attenuation in optical fibers caused by contamination from hydroxyl (OH) ions that are residuals of the manufacturing process.Water peak causes wavelength attenuation and pulse dispersion in the general regions of 950 nm, 1380 nm and 2730 nm. Low-water-peak fiber (LWPF) and zerowater-peak fiber (ZWPF) resolves water peak issues in the 1380 region (1383 nm), thereby opening the entire spectrum from 1260 to 1625 nm for high-performance optical transmission technologies employing coarse wavelength division multiplexing (CWDM). See also attenuation, CWDM, hydroxyl, LWPF, pulse dispersion, wavelength, and ZWPF.

water-blocking gel - A soft, gooey, gelatinous, hydrophobic substance used to flood outside plant (OSP) cables to protect them from moisture and even standing water. Moisture can cause electrical noise and short circuits in copper cables, ice crush in fiber optic cables, and can cause cable sheaths to crack in subfreezing temperature conditions.An alternative to the unpleasantly gooey and sticky gel is a dry powdered compound that becomes a water-blocking gel on contact with moisture. See also icky-pic and OSP.

watermark - 1. A translucent mark or image in paper produced by pressing the paper in a mold or on a processing roll during the manufacturing process. The watermark is visible when the paper is held to a light. A watermark is used as a sign of authenticity in order to make the counterfeiting of currency and postage stamps more difficult, for example. 2. Digital watermarking is the process by which visible or invisible copyright notices or other messages are embedded in audio, image, or video signals or files, program files, or Web pages, thereby providing a tracking mechanism and discouraging copyright violations. The term is derived from the practice of marking paper, especially currency and postage stamps, to discourage counterfeiting.A hidden digital watermark is a form of steganography. See also steganography.

WATS (Wide-Area Telephone Service) - A toll-free dialing service (800/888 lines) offered by telephone companies. In-WATS lines are priced and set up for incoming only calls, and sometimes calls from a certain area. You can also subscribe to Out-WATS service as well. WATS can be for interstate and intrastate long distance. If you call an 800 number, you are most likely calling an in-WATS service line that a company has set up for customers. The time to start checking into WATS service is when your long distance to or from a specific area exceeds $200.00 per month.

Watt (W) - The unit of electrical power, represented as P in Ohm’s Law formulas. Wattage is calculated by P= I x E, where P is power in watts, I is current in amps, and E is voltage in volts. For example, if you have a light bulb that draws 1 amp at 100 volts, it would be a 100-watt light bulb. The power consumed by the light bulb is radiated as heat and light. Just because a light bulb has a higher wattage rating does not mean that it is brighter, it could be hotter as well. Technically, one watt is equal to one joule per second. Another way to grasp the concept of a watt is to use the comparison that 746 watts is equal to one horsepower.

wave - Something that moves up and down, back and forth, in and out, left and right, or otherwise in a gradual, curving, or undulating motion. See also waveform.

waveform - The geometric shape of a wave.A waveform is used to graphically represent some recurring characteristic of a wave over time. Electromagnetic energy is commonly plotted in two dimensions as a sinusoidal waveform that varies in amplitude (A), or signal strength, on the vertical (V) axis at a periodic rate, or frequency (f), over time (t) on the horizontal (H) axis. See also sine wave.

waveguide dispersion - 1. A type of dispersion caused by the different refractive indexes of the core and cladding of an optical fiber. Regardless of the nature of the light source and optical fiber, some light travels in the cladding, as well as the core. Assuming a step-index fiber, the core is of one highly consistent index of refraction (IOR), and the cladding is of another, although sometimes the cladding is of several layers of glass, each with a sharp step in IOR. As the IOR of glass varies as the wavelength varies, with longer wavelengths propagating at higher velocities, as no light pulse has a perfectly narrow spectral width, and as multiple layers of glass of different properties make up the core and cladding, different wavelengths of light propagate at different velocities in the different layers. So, the optical pulse can disperse, or spread, over a distance, which clearly can confuse the light detector at the far end of the fiber.Waveguide dispersion is one factor contributing to chromatic dispersion, both of which are issues in long haul fiber optic transmission systems (FOTS) employing single-mode fiber (SMF) of step-index construction. Multimode graded-index fibers suffer so much from modal dispersion over short distances that material dispersion and chromatic dispersion never become factors. See also chromatic dispersion, dispersion, IOR, SMF, spectral width, step-index fiber, and waveguide dispersion. 2. A type of dispersion attributable to the relationship of the physical dimensions of the waveguide and the optical signal, specifically, the diameter of the fiber in cross-section and the length of the optical wave, i.e., the wavelength of the signal. The closer the relationship is to 1:1, the less the waveguide dispersion.As the waveguide increases in size from 50 microns to 62.5 microns, for example, waveguide dispersion increases at a given wavelength, such as 1300 nm.The diameter of the waveguide determines the number of modes, or physical paths, along which the signals are allowed to propagate. As the wavelength decreases from 1300 nm to 850 nm, for example, waveguide dispersion increases in fiber of a given core diameter, such as 62.5 microns.This is due to the increased frequency of the signal and, therefore, the increased opportunity for the signal to interact with the waveguide.This type of waveguide dispersion affects only multimode fiber (MMF) as single-mode fiber (SMF) supports only a single mode. See also MMF, mode, propagate, SMF, and wavelength.

Waveguide - A device used to direct radio-frequency transmissions or light waves. Waveguides in radio transmitters look like high-tech plumbing. In lightwave applications, they are a small prism or optical fiber.

wavelength band - A continuous group, or range, or wavelengths with an upper limit and a lower limit. In analog terms, bandwidth and channel width are defined as a range of frequencies.The ITU-T defines standard optical transmission windows in bands of wavelengths. See also wavelength and window.

wavelength division multiplexer (WDM mux) - A device that performs wavelength division multiplexing (WDM). See WDM.

Wavelength-Division Multiplexing (WDM) - A way of increasing a fiber optic’s capacity by using multiple colors of light. Each color of light has its own wavelength (and its own frequency). The electronic equipment on each end of the fiber can distinguish the different signals by their color (frequency/wavelength). In most applications today, each fiber optic in a communications network carries one light signal that is one pure color. In the future, fiber optic will be wavelength-division multiplexed to carry many transmission signals.

Wavelength - The wavelength of a radio signal in meters is equal to 300,000,000 m/s (the speed of light) divided by the frequency in hertz. For example, the wavelength for an FM radio station’s signal if they are at 96.3 MHz on the radio dial is equal to (300,000,000 m/s / 96,300,000 Hz =3.115 meters). It is useful to know wavelength in the design of radio antennas, which are made to be the same length or a fraction of the length of a radio signal’s wavelength.

wavelet compression - A technique for video compression that uses wavelet transforms to compress data. Wavelet compression treats the entire image as a series of small waveforms, or signals, known as wavelets, with one per color channel, e.g., red, green, and blue. A wavelet transform is applied that quantizes the wavelets by measuring the distances between the zero line and points along each wavelet and records theses distances as coefficients, with one coefficient for each pixel in the image.The coefficients of adjacent images are averaged to produce a simplified version of the wave, which process effectively halves the size of the image description.The process is repeated again and again and so on, producing progressively smaller waves, therefore, and smaller data files in a process known as decomposition.At each step of the averaging process, the difference between the coefficients is noted.Wavelet compression is used effectively to compress transient images, such as twinkling stars in a night sky.The U.S. Federal Bureau of Investigation (FBI) uses wavelet compression to store fingerprints. Smooth, periodic images are best compressed using other methods.Wavelet compression can be either lossless or lossy in nature. See also compression, lossy compression, transform, and video.

WD-40 (Water Displacement, 40th attempt) - Arguably one of the two greatest inventions of the twentieth century (duct tape is the other),WD-40 was invented by Norm Larsen on his 40th attempt to develop a formula to prevent corrosion by displacing water. In addition to displacing water,WD-40 is a multipurpose problem solver that variously cleans, removes, dissolves, degreases, penetrates, and lightly lubricates various other items.The formula for WD-40 remains a closely guarded secret.As the saying goes, “If it is stuck and shouldn’t be,WD-40 it. It if is unstuck and shouldn’t be, duct tape it.”The WD-40 Company did not pay me for this definition, but they should. See also duct tape.

WDCS (Wide-Band Digital Cross-Connect System) - Another name for DCS (Digital Cross-Connect System).

WDM (Wavelength Division Multiplexing) - A multiplexing technique by which multiple wavelengths of light, or lambdas, share a single optical fiber.Wavelength division multiplexing is essentially frequency division multiplexing (FDM) at the optical level. Much as multiple electrical frequencies can coexist on an electrified copper circuit in support of multiple, simultaneous conversations in a FDM transmission system, multiple wavelengths can coexist on a single fiber of the appropriate type in a WDM system. A number of carriers now routinely deploy dense wavelength division multiplexing (DWDM) on fiber optic systems, introducing eight or more lambdas into an optical fiber through the use of tunable, cooled lasers firing through windows, or wavelength ranges.The ITU-T has defined 160 wavelengths at spacings of 100 GHz (at 1550 nm) and manufacturers currently offer DWDM systems that multiplex as many as 80 lambdas. Coarse wavelength division multiplexing (CWDM) is defined by the ITU-T as 18 wavelengths in the 1270–1610 nm range, with spacing of 2500 GHz (at 1550 nm). See also CWDM, DWDM, FDM, lambda, laser, optical fiber, wavelength, and window.

WDM (Wavelength Division Multiplexing) - See Wavelength Division Multiplexing.

Web (World Wide Web) - See WWW.

Web 2.0 - A term coined by O’Reilly Media (2003) and referring to a second generation of the World Wide Web (WWW) as an enabling platform for Web-based communities of interest,collaboration,and hosted services.Web 2.0 supports mashing, which is a process of building new services from reusable components of other services. Applications include social bookmarking, calendaring, and VoIP. Really Simple Syndication (RSS) is one of the most popular tools associated with Web 2.0. See also RSS, VoIP, and WWW.

Web Browser - Also called a browser or an Internet browser. A computer program that allows users to download World Wide Web pages for viewing on their computers. Two popular browser programs are Netscape Navigator and Microsoft Internet Explorer. The first browser program was called Mosaic, and it was a text browser, as opposed to the newer graphical browsers.

Web clipping - Referring to the technique of stripping the graphic content out of Web pages for use in microbrowsers built into terminals used in cellular networks running the Wireless Access Protocol (WAP). Web clipping is simpler, but much less aesthetically pleasing than accessing Web sites written in WML (Wireless Markup Language), which is similar to HTML. The alternative is transcoding from HTML to WML, which is accomplished through gateways.The latter approach is commonly employed in contemporary networks, as the cost of such gateway technology has dropped considerably in the recent past, while the performance of the gateways has increased. See also cellular radio, gateway,HTML,microbrowser,WAP, and WML.

Web log (blog) - See blog.

Web page - See home page.

WECA (Wireless Ethernet Compatibility Alliance) - See Wi-Fi Alliance.

well-known port - A port reserved for the use of system (root) processes or of programs executed by privileged users for specific applications or services.Well-known ports are numbered 0 through 1023, and include 25 for SMTP (Simple Mail Transfer Protocol), 80 for HTTP (HyperText Transport Protocol), and 107 for Remote TELNET Service. See also dynamic port, port, private port, and registered port.

WEP (Wired Equivalent Privacy) - In IEEE 802.11b wireless LAN (WLAN) specifications, an optional security mechanism that uses a stream cipher with a 40-, 64- or 128-bit (WEP2) encryption key to protect data in transit. Since compromised by hackers in 2001,WEP largely has been replaced by Wi-Fi Protected Access (WPA). See also 802.11b, cipher, encryption, hacker, key, WLAN, and WPA.

Western Union - The Mississippi Valley Printing Telegraph Company, formed in 1851, became the Western Union Telegraph Company in 1856 through a series of acquisitions. Western Union completed the first transcontinental telegraph line in 1861, which put the Pony Express out of business.Western Union introduced the stock ticker in 1866, a standardized time service in 1870, and a money transfer business in 1871. In the fall of 1876, the American Bell Telephone Company offered to sell the Bell telephone patents to Western Union for $100,000.Western Union President Carl Orton reportedly replied,“What use would this company make of an electric toy?” In 1877, however,Western Union became convinced of the telephone’s importance, and began to compete fiercely against AT&T until it lost a patent lawsuit and exited the business in 1879.Western Union later was a leader in intercity fax service, microwave and satellite communications, and Telex service. On January 27, 2006, the company discontinued telegram service, and is now a financial services company. The last 10 telegrams included birthday wishes, condolences on the death of a loved one, notification of an emergency, and several people trying to be the last to send a telegram. See also fax, microwave, Pony Express, satellite, telegram, telegraph, and Telex.

Wet Circuit - A T1 circuit is a wet circuit when its 135V DC battery voltage is present. When the T1 has the battery voltage removed via a CSU/DSU (Channel Service Unit/Digital Service Unit) it is a dry T1 circuit or more commonly known as a DS1.

Wet T1 - See Wet Circuit.

White Board - Also called a mushroom board or peg board. It is placed between termination blocks (such as 66M150 blocks) to provide a means of support for routing cross-connect wire.

white light - Visible light that is a combination of all frequencies or wavelengths in the visible light spectrum. See also white noise.

White Noise - Random electrical noise, also called ambient noise. White noise is the sound you get from a TV or radio when it is not tuned to a station.

whiteboarding - A graphical conferencing technology that allows multiple users to collaborate over a network on a graphic basis as though they were drawing on a physical whiteboard. Participants can create and modify a document by clicking and dragging with a mouse, with each participant assigned a different color marker. Participants also have the use of a pointer and highlighter. See also collaborative computing.

Whois - 1. A utility on UNIX systems that provides information about other users who are logged on to the same system. See also UNIX and utility. 2. An Internet database service that provides identity and contact information about owners of domain names. See also database, Domain Name System, and Internet.

Wi-Fi (Wireless Fidelity) - The name given IEEE 802.11 by the Wireless Ethernet Compatibility Alliance (WECA, now the Wi-Fi Alliance), Wi refers to the wireless nature of the LAN and Fi to the fidelity (i.e., faithfulness, or integrity) of the signal.The term also has been attributed to the IEEE 802.11 Working Group, with Wi referring to the fact that a wire traditionally served as the physical medium for LANs, and the homonym Fi referring to PHY, the PHYsical Layer of the OSI Reference Model. So,Wireless PHY became Wi-Fi. One way or another, or perhaps both ways, Wi-Fi became the vernacular for 802.11 and especially 802.11b. See also 802.11, 802.11a, 802.11b, 802.11g, 802.11n, IEEE, OSI Reference Model, Physical Layer, and VoWiFi.

Wi-Fi Alliance - Previously the Wireless Ethernet Compatibility Alliance (WECA). A special interest group comprising manufacturers and vendors that work to develop specifications for and promote the worldwide adoption of products based on the IEEE 802.11 standards for wireless local area networks (WLANs). See Appendix A for contact information. See also 802.11, IEEE, and WLAN.

Wi-Fi Multimedia Extension (WMM or WME) - The term the Wi-Fi Alliance uses for the priority classes specified in IEEE 802.11e for quality of service (QoS) over 802.11 wireless LANs (WLANs). See also 802.11, 802.11e, IEEE, QoS, Wi-Fi Alliance, and WLAN.

Wi-Fi Protected Access (WPA) - See WPA.

Wi-Fi TV - A term sometimes used for the wireless regional area network (WRAN) project of the IEEE 802.22 Working Group.Wi-Fi TV is intended to operate in the UHF and VHF broadcast TV bands. See also 802.22 and WRAN.

Wi-Fi5 (Wireless Fidelity 5 Ghz) - The vernacular for IEEE 802.11a. See 802.11a and Wi-Fi.

WiBro (Wireless Broadband) - A wireless local loop (WLL) specification developed by the government of South Korea.WiBro allocates 100 MHz of spectrum set in the 2.3 GHz band, offers aggregate throughput of 30–50 Mbps, and has a reach of 1–5 kilometers. See also BRAN, WiMAX, and WLL.

Wicked Witch of the West (WWW) - A wicked witch played by Margaret Hamilton in the 1939 film “The Wizard of Oz.” Ms. Hamilton often used WWW in autographing photos of herself in costume.The most oft-quoted line of the Wicked Witch of the West, whose real name was never revealed, is “I’ll get you, my pretty — and your little dog, too!” Dorothy, however, was protected by Glinda, the Good Witch of the North.Alas, Good does not always triumph over Wickedness in the real world. See also WWW.

Wide Area Network (WAN) - See WAN.

Wide Area Telecommunications Service (WATS) - See WATS.

Wide Band - Another name for Broadband. Incorporating more than one channel into a communications transmission. T1 is a broadband communications protocol because it carries 24 conversations over four wires. Cable TV is also broadband because it carries many TV channels over one coax.

Wide-Area Network (WAN) - See WAN.

Wide-Band Division Multiplexing - The transmission of multiple SONET transmissions over a single fiber-optic pair. Each SONET transmission is sent via a different frequency (or color) of light. This method is used to obtain an OC-768 with four OC-192 transmissions of different frequencies.

Wideband CDMA (W-CDMA) - Also known as Universal Mobile Telecommunications System (UMTS). See UMTS.

wideband - 1. A circuit or channel with capacity greater than narrowband. See also narrowband. 2. A circuit or channel with bandwidth wider than normal for operation. See also bandwidth. 3. A radio channel covering a relatively wide range of frequencies. Ultra-Wideband (UWB) for example, is a radio system with occupied bandwidth (i.e., the difference between the highest and lowest frequencies in the radio channel) greater than 25 percent of the center frequency. See also bandwidth. 4.Wideband sometimes is used interchangeably with broadband. See also broadband. (I promise that I don’t make these things up. I just explain them as they are).

wiki - 1. Quick or fast, in the Hawaiian language. 2. A type of authoring software that enables users to easily and quickly create and edit Web server content using any browser.

Wildcard Mask - A 32-bit quantity used in conjunction with IP addresses to determine which bits in an IP address should be ignored when comparing that address with another IP address. A wildcard mask is specified when setting up access lists.

WiMAX (Worldwide Interoperability for Microwave Access) - A broadband wireless access (BWA) solution based on the standards recommendations from the IEEE 802.16 Working Group and the European Telecommunications Standards Institute (ETSI) HiperMAN group. WiMAX is promoted by the WiMAX Forum, a special interest group with members from the manufacturing, carrier, service provider, and consulting communities.Where line of sight (LOS) can be achieved, the WiMAX cell radius is as much as 50 kilometers (31 miles). Under non-line of sight (NLOS) conditions, the maximum cell radius is approximately 9 kilometers (5.6 miles). WiMAX standards provide for aggregate raw bandwidth up to about 70 Mbps per base station (BS), although the throughput is much less due to overhead, as well as issues of LOS, link distance, air quality, electromagnetic interference (EMI), radio frequency interference (RFI), and other signal impairments. Mobile network deployments described in 802.16e are expected to provide up to 15 Mbps of aggregate raw bandwidth within a cell radius of up to 3 kilometers.WiMAX supports a maximum signaling rate of 70 Mbps and the maximum throughput of approximately 40 Mbps over the shortest distance between the BS and the user antenna under LOS conditions. Over the maximum distance of 50 kilometers under LOS conditions, or the maximum distance of 9 kilometers under NLOS conditions, throughput drops considerably.The transmission rate is symmetrical, i.e., the same for the uplink (upstream), i.e., the link from the remote terminal back to the BS, as for the downlink (downstream).The sole exception to this symmetry is in the case of full-featured CPE at the cell edge, where uplink transmission rates are constrained by power limitations. WiMAX employs orthogonal frequency division multiplexing (OFDM), which subdivides the spectrum into a number of independent, narrowband subcarriers, across which it sends the signal in parallel fashion.Through sub-channelization on the uplink,WiMAX concentrates signal power into fewer OFDM subcarriers, thereby extending the reach of the system, mitigating the effects of physical obstructions in an NLOS environment and reducing CPE power consumption. Multiple-input multiple-output (MIMO) antennas employ space/time coding to compensate for multipath fading over long loops.At the customer premises is an adaptive, passive array antenna known as a pizza box, as it is about the size and shape of a pizza box. Rate-adaptive modulation dynamically adjusts the signal modulation technique of each carrier to compensate for variations in signal quality at that carrier frequency. Reed-Solomon forward error correction (FEC) is employed to deal with issues of signal quality and automatic repeat request (ARQ) is employed to request retransmission of any remaining errored frames. 802.16 specifications include several multiplexing options. Frequency division duplex (FDD) supports both half-duplex (HDX) and full duplex (FDX) communications, and time division duplex (TDD) supports half-duplex (HDX), only.The 802.16 security protocol is built on enhancements to the privacy key management (PKM) developed for cable modem communications.The protocol uses X.509 digital certificates with Rivest-Shamir-Adleman (RSA) encryption for authentication and key exchange.Traffic encryption options are data encryption standard (DES) and advanced encryption standard (AES). 802.16 specifications include convergence sublayers designed for mapping services to and from 802.16 connections. The ATM convergence sublayer is for ATM services and the packet convergence sublayer is for packet services such as IPv4, IPv6, Ethernet, and Virtual LAN (VLAN). WiMAX offers differential quality of service (QoS) based on four polling schedules:

• Unsolicited grant service (UGS) is designed for services such as T1 and E-1.

• Real-time polling service is designed for services such as voice over Internet Protocol (VoIP) and IPbased streaming audio and video.

• Non-real-time polling service is designed for services such as Internet access.

• Best effort service provides neither throughput nor latency guarantees.

See also 802.16, AES, ARQ, ATM, authentication, base station, broadband, BWA, cable modem, carrier, DES, digital certificate,E-1,EMI,encryption,Ethernet,ETSI,FDD,FDX,FEC,HDX,HiperMAN,IPv4,IPv6, latency, LOS, MIMO, modulation, narrowband, NLOS, OFDM,overhead, pizza box, PKM, protocol, rate adaption, ReedSolomon, RFI, RSA, signal, subcarrier, T1, TDD, throughput, VLAN, VoIP, WiMAX Forum, and X.509.

WiMAX Forum - A not-for-profit organization formed to promote and certify the compatibility and interoperability of broadband wireless access (BWA) products based on the IEEE 802.16 and ETSI HiperMAN specifications. For contact information, see Appendix A. See also 802.16, BWA, ETSI, HiperMAN, IEEE, and WiMAX.

window - 1. An opening or opportunity for passage of data frames or packets without the requirement for an acknowledgement from the receiving device. See modulo and TCP. 2. An opening or opportunity for passage of a range of wavelengths in a fiber optic transmission system (FOTS). For example, a laser diode might fire at 1550 nm, referring to a range of wavelengths with a nominal center point of 1550 nm. A light-emitting diode (LED) might fire at 850 nm, and a vertical cavity surface-emitting laser (VCSEL) at 1300 nm or 1310 nm.The ITU-T has established a number of standard windows. Generally speaking, the higher the transmission window (i.e., the longer the wavelength and lower the frequency), the less the signal attenuation, but the more expensive the associated electronics. See also attenuation, FOTS, frequency, laser diode, LED, VCSEL, and wavelength.

Band Designation	Wavelength Window
850 Band	810–890 nm
O-Band (Original Band)	1,260 nm–1,360 nm
E-Band (Extended Band)	1,360 nm–1,460 nm
S-Band (Short Wavelength Band)	1,460 nm–1,530 nm
C-Band (Conventional Band)	1,530 nm–1,565 nm
L-Band (Long Wavelength Band)	1,565 nm–1,625 nm
U-Band (Ultralong Wavelength Band)	1,625 nm–1,675 nm

ITU-T Transmission Windows

Wink Start Signal - Another name for a hookflash that is sent by PBX systems to telephone company central-office switches that signals a request for dial tone or other services. Wink start signaling is slowly being replaced by T1 out-of-band signaling, which is much faster, offers many more services, is less expensive, and is, of course, digital.

Wink - Another name for a hookflash that is sent by PBX systems to telephone company central-office switches that signals a request for dial tone or other services.

wiper - Also known as a selector, a wiper is a component of a step-by-step (SxS) electromechanical circuit switch. See selector.

Wire Center - A reference to a telephone company central office’s geographical service area. The central office serves the area that its telephone wires (outside plant) reach to.

Wire Pair - A reference to two solid wires, twisted together, usually just called a pair. For more information, see UTP.

Wire Tap - A device used to monitor telephone lines. With newer technology, the telephone company is capable of tapping or monitoring a telephone line with a stroke of a few keys. They can even set the telephone line to be monitored by a different telephone line, anywhere they want. Telephone companies (especially the Bell Companies) have extremely strict security guidelines regarding the monitoring of telephone conversations. They will not set up a tap or a monitor service without legal procedures being followed according to the laws of the area they are operating in. Watch-dogs are in place to be sure that telephone company employees do not monitor telephone lines when they are not supposed to. Some “spy” shops sell telephone line-tapping and recording devices, but I would not recommend the use of them because of strict laws regarding telephone privacy.

Wire-Wrap Termination - A type of twisted-pair wire termination used on DSX panels and other digital telecommunications services processing equipment. Wire-wrap termination is used because it requires very little space, compared to 110 blocks or 66M150 blocks.

wire - A current-carrying metal conductor, generally encased in a dielectric insulating material. A solid core conductor comprises a single wire. A stranded conductor comprises a number (usually 7 or 17, because they pack neatly) of small wires.Telecommunications wires generally are made of copper to conduct electrical current, although tinned copper, copper-clad aluminum, and other metals and metal combinations also can be used. Stranded, rather than solid core, conductors are used in applications requiring high flex strength. The wires generally are separately insulated with polyethylene, polyvinyl chloride (PVC), flouropolymer resin,Teflon, or some other low-smoke, fire-retardant, dielectric material.Two wires then typically are twisted in a helix with a constant pitch or distance to make a 360-degree twist to form a twisted pair. One or more pairs then are formed into a cable, which is covered in a protective sheath of dielectric material. See also cable, conductor, current, dielectric, flex strength, insulation, and twisted pair.

wired equivalent privacy (WEP) - See WEP.

Wireless Access Communication System (WACS) - See WACS.

Wireless Access Protocol (WAP) - See WAP.

Wireless Broadband (WiBro) - See WiBro.

Wireless Ethernet Compatibility Alliance (WECA) - See Wi-Fi Alliance.

wireless fiber - A term sometimes applied to free space optics (FSO) systems, which are optical airwave systems operating in the infrared (IR) spectrum and offering bandwidth up to the Gbps range. See also bandwidth, infrared, FSO, and spectrum.

Wireless LAN - A local-area network of computers and peripheral devices that communicates via radio signals or light waves (low-power laser beams). These systems are useful in situations where the cost of installing wiring between the devices is very expensive or for temporary/ mobile applications.

wireless local area network (WLAN) - See WLAN.

wireless local loop (WLL) - See WLL.

wireless local number portability (WLNP) - Synonymous with wireless number portability (WNP). See WNP.

Wireless Markup Language (WML) - See WML.

wireless media - See transmission medium.

Wireless Medical Telemetry Service (WMTS) - See WMTS.

wireless number portability (WNP) - See WNP.

wireless office telecommunications system (WOTS) - See WOTS.

wireless personal area network (WPAN) - See WPAN.

wireless regional area network (WRAN) - See WRAN.

Wireless Transport Layer Security (WTLS) - See WTLS.

wireless - Referring to a link, circuit, or network that employs either radio frequency (RF) or infrared (IR) transmission medium, rather than a wired technology such as coaxial cable, twisted pair, or optical fiber. See also coaxial cable, IR, RF, optical fiber, transmission medium, and twisted pair.

wireline carrier - Also known as a B Carrier.A provider of traditional landline telecommunications services. Such services involve connections to the public switched telephone network (PSTN) by wire (or fiber) local loops that terminate in fixed locations at customer premises.The distinction between wireline and non-wireline carriers was made primarily for purposes of segregating bidders for radio spectrum assignment during the FCC cellular radio spectrum auctions.The initial approach toward spectrum assignment was designed to ensure that there was one wireline (i.e., telephone company) and one non-wireline carrier per market. See also carrier, cellular radio, FCC, landline, local loop, premises, PSTN, radio, and spectrum.

wireline - Referring to a service that connects to the public switched telephone network (PSTN) through a local loop of copper wire or glass fiber that terminates in a fixed location at a customer premises.A wireline service is in contrast to a wireless local loop (WLL) and a wireless service such as cellular. See also cellular radio, fiber, PSTN, wire, wireless, and WLL.

wiretap - In historical terms, a temporary physical connection secretly placed on a metallic circuit in order to monitor the information being transmitted across it. In contemporary terms, a wiretap need not be a physical connection on a circuit, but can take many forms, including the interception of a radio signal. In the United States and many other countries, wiretaps are illegal unless authorized by court order, or perhaps the order of a federal agency or of the executive branch of government in times of war or in the interests of national security. See also eavesdrop and Echelon.

WIS (WAN Interface Sublayer) - A protocol sublayer that enables compatibility between 10 Gigabit Ethernet (10GbE) equipment and SONET long-haul equipment in a LAN-to-WAN interface scenario. See also 10GbE, LAN, long haul circuit, SONET, and WAN.

WLAN (Wireless Local Area Network) - A LAN that employs radio frequency (RF) or perhaps infrared (IR) transmission rather than a wired technology such as coaxial cable, twisted pair, or optical fiber. A typical WLAN comprises fixed-location transceivers known as access points (APs) to which client workstations and peripherals connect via RF technology.The access points typically are hard wired to switches and routers that interconnect them and provide access to servers.The APs are fitted with radio transceivers and omnidirectional antennas.The client transceivers, or network adapters, may be in the form of PCMCIA cards, although major computer manufacturers now offer laptops with built-in transceivers.The APs are located at central points where there is good line of sight (LOS) to the workstations and link quality, therefore, is best. Most WLANs are standards-based versions from the IEEE 802.11 Working Group.At the Physical Layer, the RF specifications include both direct sequence spread spectrum (DSSS) and frequencyhopping spread spectrum (FHSS). At the Data Link Layer, the medium access control (MAC) protocol is carrier sense multiple access with collision avoidance (CSMA/CA). Most WLANs operate in the 2.4 Ghz and 5 GHz unlicensed ISM (Industrial, Scientific, and Medical) bands, which approach avoids the expensive and lengthy licensing process, but carries with it the potential for interference from other systems in proximity. As power levels are low, distances generally are limited to 500–800 feet or so. See also 802.11, AP, coaxial cable, CSMA/CA, Data Link Layer, DSSS, FHSS, hardwire, IR, ISM, LOS, MAC, RF, router, switch, optical fiber, Physical Layer, switch, transceiver, transmission medium, and twisted pair.

WLL (Wireless Local Loop) - Also known as fixed wireless. A group of airwave transmission technologies designed to support communications from the edge of a public network to the customer premises. These fixed wireless technologies include both radio frequency (RF) and infrared (IR) options. RF solutions include Local Multipoint Distribution Service (LMDS), Multichannel Multipoint Distribution Services (MMDS), and Worldwide Interoperability for Microwave Access (WiMAX). Free space optics (FSO) systems are wireless optical transmissions using wavelengths in the infrared range.The technologies supporting broadband performance to an individual user are sometimes known as broadband wireless access (BWA) and include all of the above. See also airwave transmission, BWA, FSO, IR, LMDS, local loop,MMDS, RF, and WiMAX.

WLNP (Wireless Local Number Portability) - Synonymous with wireless number portability (WNP). See WNP.

WMBTOTCITBWTNTALI (We May Be The Only Telephone Company In Town, But We Try Not To Act Like It) - Southwestern Bell Telephone Company used this initialism in an advertising campaign during the 1970s. The campaign backfired, of course, because a substantial number of people felt very strongly that the company did try to act like it. Sometimes they were right. (I worked for the company in management at the time, so I know.) The ad campaign was short-lived, but the company was not. Southwestern Bell later changed its name to SBC, and merged with and acquired a number of companies outside the southwest region of the United States. One of those acquisitions was the remnants of the once great AT&T, which had been Southwestern Bell’s parent company until the breakup of the Bell System in 1984. SBC assumed the name in 2006, and is now known as AT&T.

WMM (Wi-Fi MultiMedia extension) - See Wi-Fi Multimedia Extension.

WMTS (Wireless Medical Telemetry Service) - In the United States, a service that supports the remote monitoring of a patient’s health for medical purposes. All types of communications other than voice and video are permitted as long as they relate to the provision of medical care.WMTS operates in the 608–614 MHz, 1395–1400 MHz, and 1427–1432 MHz bands.The Federal Communications Commission (FCC) regulates WMTS, which is in the family of personal radio services. See also FCC and personal radio services.

WNP (Wireless Number Portability) - Also known as full mobile number portability (FMNP) and wireless local number portability (WLNP). Referring to the ability to port, i.e., move, a cellular telephone number from one carrier to another. Local number portability (LNP) is the equivalent term in the fixed-line, or wireline, domain. See also carrier and LNP.

Word - In computer memory, a word is 16 bits, which is one data unit processed by the bus. Newer computers and other processing systems are built with 32- and 64-bit busses, which gives them the ability to process double words (32 bits) and quad words (64 bits).

workgroup switch - In a local area network (LAN), a workgroup switch is a relatively low capacity switch that serves the needs of a workgroup, or small group of workers who generally are geographically clustered. A workgroup switch is the LAN equivalent of an edge switch in a public wide area network (WAN). See also backbone switch, LAN, switch, and WAN.

World Administrative Radio Conferences (WARC) - Now known as the World Radio Conferences (WRC). See WRC.

World Radio Conferences (WRC) - See WRC.

World Trade Organization (WTO) - See WTO.

World Wide Web (WWW) - The Graphical User Interface (GUI) system that makes finding information on the Internet easier by organizing it into pages. WWW also provides hyperlinks, which, when “clicked on” with a mouse, take you to the corresponding page (it is actually another address) that contains the implied information.

World Wide Web Consortium (W3C) - An international partnership of companies that are involved with Internet and the World Wide Web that was founded in 1994 by Tim Berners-Lee. The purpose of W3C is to oversee the development of open standards to evolve the Web in a uniform manner that is usable by everyone and to prevent competing factions from implementing proprietary browser formats. The W3C is the chief standards organization for HTTP (Hypertext Transfer Protocol) and HTML (Hypertext Markup Language).

Worldwide Interoperability for Microwave Access (WiMAX) - See WiMAX.

worm - A type of malware that replicates itself across a computer network by making copies of itself, which it sends to other computers. A worm embeds itself in memory and may replicate itself so many times that it causes the host to crash. Note that a worm is neither a Trojan horse nor a virus. See also malware, spyware, Trojan horse, and virus.

WOTS (Wireless Office Telecommunications System) - A wireless telephone system generally in the form of one or more adjuncts that provide cordless telephony communications capabilities behind PBXs, electronic key telephone systems (EKTS), or Centrex systems.WOTS generally are limited to voice applications, although some also support low-speed data. WOTS systems involve a wireless master controller, which is hardwired to special ports on the voice communications system. See also adjunct, Centrex, cordless telephone, EKTS, hardwire, PBX, and port.

WPA (Wi-Fi Protected Access) - A security mechanism based on IEEE 802.11i,WPA was designed by the Wi-Fi Alliance to replace the flawed Wired Equivalent Privacy (WEP) for 802.11b, aka Wi-Fi, wireless LANs (WLANs).WPA2 includes an encryption algorithm based on Advanced Encryption Standard (AES), which employs a 128-bit block cipher that is considered to be completely secure. See also 802.11b, 802.11i, AES, block cipher, encryption, WEP, and WLAN.

WPAN (Wireless Personal Area Network) - A wireless network defined by personal operating space (POS), which simply is the area in the near vicinity of a device or individual. 802.15 is the IEEE specification for WPANs and 802.15.1 is the specification for Bluetooth. See also 802.15 and Bluetooth.

WRAN (Wireless Regional Area Network) - A technology under development by the IEEE 802.22 Working Group directed toward the development of a cognitive radio air interface for use by licenseexempt radios on a non-interfering basis in spectrum currently allocated to television broadcast service. See also air interface, cognitive radio, IEEE, and spectrum.

wrap - A restoral mechanism employed in Resilient Packet Ring (RPR). In the event of a node or link failure, wrap calls for data to travel around the fiber optic ring until it reaches the node nearest the break. That node turns the traffic around and sends it in the reverse direction over the counter-rotating ring. See also dual counter-rotating ring, fiber optics, link, node, RPR, and steer.

WRC (World Radio Conferences) - Previously known as the World Administrative Radio Conferences (WARC). A group of conferences at which the various national regulatory authorities meet to sort out national and international spectrum allocation issues.WRC are sponsored by the ITU-R every two years. See also ITU-R.

WTLS (Wireless Transport Layer Security) - Pronounced witless. The security layer that provides authentication services for the Wireless Access Protocol (WAP) used in many Web-enabled cellular networks. See also authentication, cellular radio, WAP, and WWW.

WTO (World Trade Organization) - An international organization that deals with the global rules of trade between nations.The WTO was formed in 1995 as the successor to the Global Agreement on Tariffs and Trade (GATT), which was established in 1955 in the wake of World War II (WWII). In the context of telecommunications, the WTO’s involvement largely has been in the realm of international long distance rates.

WWW (World Wide Web) - The Graphical User Interface (GUI) system that makes finding information on the Internet easier by organizing it into pages. WWW also provides hyperlinks, which, when “clicked on” with a mouse, take you to the corresponding page (it is actually another address) that contains the implied information.

WYSIWYG (What You See Is What You Get) - Pronounced wizzywig. Referring to a program that allows the user to see the document on screen just as it will appear in final form.Working with a word processing program in print view is WYSIWYG. Programming in a markup language such as HTML definitely is not.