On-Line Encyclopedia - U

The Maui Communications Networks
On-Line Encyclopedia

Alphabetical List Of Definitions For Technical Terms

U
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Ultra Wideband (UWB)
UWB (IEEE 802.15.3a) is a radio communication technology designed for short-range, wireless personal area networks (WPAN's) in, roughly, a 30-foot radius from the UWB transmitter. In this regard, UWB competes with 802.15 BlueTooth for WPAN connectivity. UWB is designed to operate in the 3.1 GHz to 10.6 GHz frequency range with transmit power levels as high as -41 dBm (compared to receive sensitivities as low as -95 dBm in Wi-Fi networks). The higher power levels associated with UWB are balanced against the way the RF signal is spread out (hence the name: ultra wide band). The spreading makes the UWB signal look like background noise to other communicators in the band, minimizing interference.

URL (Uniform Resource Locator)
A URL is a text string (like "https://www.connect802.com") that identifies a resource on the Internet. While a URL is commonly associated with a website it can be an identifier for a specific file, or for a specific program. The URL includes a protocol identifier (http://, https://, ftp://, telnet://), followed by a hierarchical name for the resource. The hierarchy always ends with one of the "top level domains". Top level domains were first defined in 1985 (eight years prior to the creation of the World Wide Web) and evolved from that point. The original top-level domains were: .com, .edu, .gov, .net, .org, .mil

Later, two-letter top level domains were introduced for each country, based on the ISO 3166-1 Country Code specification.
Since that time additional top level domains have been added, including: .aero, .biz, .coop, .int, .museum, .name, .pro, and many others.

You may notice that in the lists above the .tv domain was not specifically listed. That's because it was actually already defined in ISO 3166-1. The small Pacific Island nation of Tuvalu (near Australia and New Zealand) was assigned the .tv country code. In a successful venture to raise $50-Million dollars for its approximately 10,000 residents, they entered into a perpetual agreement with a company founded for the purpose of registering names in the .tv domain: The .TV Corporation.
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