Summary

IEEE 802.11 13Hardware Compatibility List (HCL) A utilitythat verifies that existing hardware is compatiblewith an operating system.hardware firewall A hardware device that filtersdata packets from the network before reaching computersand other devices on a network.Hayes-compatible command set A set of AT commandsthat most modem software uses. This commandset is named after the Hayes MicrocomputerProducts Company, which first defined it.headphone jack A socket that is used to attach anaudio output device.heat sink and fan assembly A device that dissipatesheat from electronic components into the surroundingair.hot-swappable interface Allows peripherals to bechanged while the system is running. USB is anexample.hub 1) Generally, a term used to describe a Layer 1device at the center of a star topology network. 2) Ahardware or software device that contains multipleindependent but connected modules of network andinternetwork equipment. Hubs can be active (wherethey repeat signals sent through them) or passive(where they do not repeat, but merely split, signalssent through them). 3) In Ethernet and IEEE 802.3,an Ethernet multiport repeater, sometimes called aconcentrator.Hypertext Markup Language (HTML) A pagedescriptionlanguage used by browser applicationssuch as Windows Internet Explorer and MozillaFirefox.hex driver A driver used to tighten nuts.Sometimes called a nut driver.Hypertext Transfer Protocol (HTTP)how files are exchanged on the Internet.Governshibernate/standby indicator LED A light thatshows if the computer is in standby or hibernatemode.hierarchical star topology An extended star topologyin which a central hub is connected by verticalcabling to other hubs that are dependent on it.High Data Rate DSL (HDSL)of 768 kbps in both directions.Provides bandwidthHigh-Definition Multimedia Interface (HDMI)A video, plasma, LCD, or DLP projector.HKEY_ The designation at the beginning ofWindows Registry boot filenames.host A computer system on a network. Similar tothe term node, except that host usually implies acomputer system. Node generally applies to any networkedsystem, including access servers and routers.Iicon An image that represents an application or acapability.IEEE 802.1 An IEEE specification that describesan algorithm that prevents bridging loops by creatinga spanning tree. This algorithm was invented byDigital Equipment Corporation. The Digital algorithmand the IEEE 802.1 algorithm are not exactlythe same, nor are they compatible.IEEE 802.11 An IEEE standard that specifies carriersense media access control and physical layerspecifications for 1- and 2-Mbps wireless LANs.