 earth to a satellite. Upstream: - A communications channel that sends data from earth to a satellite. UWB: - See Ultra wideband radio. VCSEL: - See Vertical Cavity Surface Emitting Laser. Vehicular telematics: - Vehicle-based information, entertainment, and navigation systems. Vertical Cavity Surface Emitting Laser (VCSEL): - A laser diode that emits light from its surface rather than its edge. Voice over Internet protocol (VoIP): - A form of IP telephony that allows people to place telephone calls over Internet connections. Voice recognition: - The conversion of spoken words into computer-usable data. VoiceXML: - An XML extension for creating telephone-based, speech-user interfaces. VoIP: - See Voice over Internet protocol. WAN: - See Wide area network. Waveguide: - A device for confining and directing electromagnetic waves. Wavelength division multiplexing (WDWM): - A technology that utilizes multiple lasers to send several wavelengths of light simultaneously over a single optical fiber. Each signal travels within a separate color band. WDWM: - See Wavelength division multiplexing. Wearable computer: - A computer that can be attached to its user's body or worn as a garment. Webconference: - A text, audio or text/audio/video conference of geographi- cally dispersed people using the Internet's World Wide Web. Web services: - Software that knows how to talk to other types of software over a network. A Web service can be nearly any type of application that has the ability to define to other applications what it does and can perform that action for authorized applications or parties. Wide area network (WAN): - A computer network that serves users in multiple locations, may be regional, nationwide or even global in scope. Wi-Fi: - A certification for 802.11 wireless network products that comply with Wi-Fi Alliance specifications. Also used as a slang term for 802.11 wireless network products in general. Wi-Fi Alliance: - A trade organization of 802.11 wireless network product vendors. GLOSSARY Wireless local area ne