The terminology in a segment as fast-moving as wireless can make one's head spin. Evolving technology, new products, and competing standards mean that today's buzzword is tomorrow's archaic term. The following glossary isn't comprehensive--one could make a book out of wireless terms, except that it would be obsolete the day of publication. But we hope it provides a handy cheat sheet when you're learning about wireless.

1G, 2G, etc: Shorthand for the various stages of evolution of wireless technology. A 1G (first-generation) wireless systems uses analog transmission; 2G uses digital; 3G, the previous standard, uses broadband technology; and 4G offers data transmission speeds of 10Mbps and up, and is meant for transmission of high-bandwidth material such as movies.

802.11: Specifications for wireless local area networks (WLANs) developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). There are currently four specifications: 802.11, 802.11a, 802.11b (Wi-Fi), and 802.16 (WiMax).

Access point: A base station in a WLAN that lets users use wireless networking cards in their computers and other electronic devices. Access points are typically standalone devices that plug into an Ethernet hub or server. One access point should provide up to 300 feet of wireless network coverage. Users should be able to roam between access points and be seamlessly handed off from one access point to another.

Ad hoc mode: A wireless network framework in which devices can communicate directly with one another without using an access point or a connection to a regular network.

Air interface: A wireless network's operating system, it allows communication between a cell phone and its carrier. The main interface technologies are AMPS, TDMA, CDMA, and GSM.

AMPS: Advanced mobile phone service, the standard for analog cell phones, using an FM transmission signal.

BlackBerry: A popular brand of mobile e-mail devices that runs on a narrowband wireless network. T-Mobile's Sidekick is another top brand in this category.

Bluetooth: A global technology standard that connects phones, computers, appliances, and other devices over short distances without wires by using low power radio frequencies. Bluetooth-enabled devices can usually communicate at distances of more than 100 yards.

CDMA: Code division multiple access, a digital wireless technology that allows large amounts of voice and data to be transmitted on the same frequency. The second-most commonly used mobile phone standard after GSM.

CDPD: Cellular digital packet data technology, used by carriers to transfer data to users via unused analog cellular networks. If one part of the network is overburdened, CDPD can automatically reallocate network resources to handle the extra traffic.

Data compatible: A wireless feature that enables devices to transmit data either from a handset or via a data card.

Data interface: Also called a data link, an accessory that allows the connection of wireless devices to computers, fax machines, or other devices.

Dead spot: An area within a wireless network where service is not available. Soon to be obsolete if wireless providers are to be believed.

Dual-band: A wireless phone that can operate on both 800MHz and 1900MHz digital networks to send and receive calls.

Dual-mode: A wireless phone that works on both analog and digital networks.

EDGE: Enhanced data for global evolution, an extension of GSM that gives users access to broadband and multimedia services such as video clips.

Fixed wireless: The operation of wireless devices or systems in homes and offices, and in particular, equipment connected to the Internet via specialized modems.

GPS: Global positioning system, a system for determining the location of a car or a person. By triangulation of signals from three of 24 satellites, a receiving unit can pinpoint its location anywhere on earth to within a few yards. The location can be displayed on a map in a car, or on the display of a mobile phone.

GSM: Global system for mobile communication, the most commonly used mobile telephone system. Primarily used for voice communication, but also able to transfer data and enable Internet use from a laptop via a GSM phone.

Handoff: The process of transferring an ongoing wireless call or data session from one channel connected to the core network to another without interruption.

HomeRF: Home radio frequency, a short-range wireless technology that uses the license-free frequency band 2.4GHz. HomeRF supports both wireless audio and data.

Hotspot: A place that offers Wi-Fi access. Hotels, restaurants, and airports commonly contain hotspots.

HSCSD: High-speed circuit switched data, a system that enables the transmission of data over GSM networks at speeds up to 43.2Kbps. HSCSD uses multiple channels to reach the high speeds.

IEEE 802.11: A family of open standards for wireless technology, developed by the Institute of Electrical and Electronic Engineers and mainly consisting of four standards:802.11, 802.11a, 802.11b, and 802.11g. The most popular current standard, 802.11g, offers wireless transmission over relatively short distances at up to 54Mbps, compared with the 11Mbps of 802.11b. Other standards (c-f, h-j, n) are service enhancement and extensions, or corrections to previous specifications.

IrDA: Infrared technology that allows cell phones, PDAs, and other devices to connect to each other wirelessly. IrDA requires line-of-sight transmission similar to that used by a TV remote control.

MAC: Media access control. Every wireless 802.11 device has a unique MAC address hard-coded into it. This identifier can be used to provide security for wireless networks.

Micro-browser: A Web browser designed to run in the low-memory, small-screen environment of a handheld device.

Mobile commerce: The use of radio-based wireless devices such as cell phones and PDAs to conduct business-to-business and business-to-consumer transactions over wired, Web-based e-commerce systems.

Portable wireless: The operation of autonomous, battery-powered wireless devices or systems outside the office, home, or vehicle.

Roaming: Movement of a mobile device from one wireless network location to another without a loss of connectivity.

Smart phone: A wireless phone with text, Internet, and--more and more frequently--multimedia capabilities.

TDMA: Time division multiple access divides a radio frequency available to a network into time slots and then allocates slots to multiple calls. Therefore, one frequency can support multiple, simultaneous data channels. TDMA is used within the GSM digital cellular system.

Texting: Also called SMS (short message service), it allows the transmission of short text messages among mobile devices such as cell phones, fax machines, and BlackBerry devices. Messages appear as text on the display screen of the receiving device.

Transport Layer Security: A protocol that ensures privacy between communicating applications and their users over WLANs and the Internet.

UMTS: Universal mobile telecommunications system, a 3G cellular network technology operating in 25 countries as of mid-2005. The transmission rates range from a theoretical 384Kbps for phones in moving vehicles up to 2Mbps for stationary devices.

WAP: Wireless Application Protocol, specifications that let developers using WML build networked applications designed for handheld wireless devices.

Wardriving: Driving around with a laptop or a PDA, looking for vulnerable Wi-Fi wireless networks. While some wardrivers do this only to find strong wireless signals to tap in to for free, some search for open file servers from which to copy software or media files.

WASP: Wireless application service provider, a vendor that provide hosted wireless applications so that companies will not have to build their own wireless infrastructures.

Wi-Fi: Wireless fidelity, the accepted term for 802.11 technology.

Wi-Fi Alliance: A nonprofit international association formed to certify interoperability of WLAN products based on the IEEE 802.11 specification. The goal of the Wi-Fi Alliance's members is to enhance end-user satisfaction by promoting interoperability between wireless products.

WiMax: Worldwide Interoperability for Microwave Access. The new wireless metropolitan-area network standard, WiMax has a range of up to 31 miles, and is primarily aimed at making broadband network access widely available without the expense of stringing wires and without the distance limitations of DSL

WinCE: A version of the Windows operating system designed for small devices such as PDAs.

WLAN: Wireless local-area network. These networks use radio waves instead of a cable to connect a user device, such as a laptop computer, to a LAN. They provide Ethernet connections over the air and operate under the 802.11 family of specifications.

WLL: A wireless local loop, or the connection between a household and the ordinary telephone network of the phone company. When using WLL, a wireless link is used instead of the traditional copper wiring.

WMAN: Wireless metropolitan area network. A regional wireless computer or communication network spanning the area covered by an average to large city. WiMax standards are meant to address WMAN demands.

WML: Wireless Markup Language. WML is comparable to the Internet programming language HTML in that it delivers Internet content to small wireless devices, such as browser-equipped cell phones, and other handheld devices that typically have small displays, slow CPUs, limited memory, low bandwidth, and restricted user-input capabilities.

WPA: Wi-Fi Protected Access, a data-encryption specification for 802.11 wireless networks that replaces the weaker wired-equivalent privacy (WEP) protocol. WPA2, the current standard, is an enhanced version of WPA.

WPAN: Wireless personal-area network, or a close-proximity network where connections are made on the fly and temporarily. Two people in a meeting, for instance, would use a WPAN to connect their Bluetooth-enabled notebooks and converse.

Zigbee: A a wireless standard that boasts low cost and low power consumption via RF technology. Common applications include building automation, electrical, and heat controls.