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10BaseT - A synonym for the Ethernet networking standard. The 10 refers to a maximum data-transfer rate of 10 megabits per second over twisted-pair wiring.

802.11 - A set of IEEE standards for data transmission over wireless LANs. The specs include 802.11, 802.11a, 802.11b, and 802.11g. All of the specifications use the Ethernet protocol.

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access point - Wirelessly networked devices usually connect to a wired LAN through a hardware device called an access point. An access point can also be one of the capabilities offered by a gateway, node or other networking device.

ad-hoc mode - Also known as peer-to-peer mode or IBSS, ad-hoc mode lets wirelessly networked devices communicate directly, without going through an access point or other intermediary.

adapter - An adapter comes in many forms, but it's essentially a device that connects to or installs into your computer, adding a specific capability or feature. The most common example is a circuit board, such as a graphics card or a NIC, that installs into a PCI or other kind of expansion slot on a desktop computer's motherboard; it's also known as an expansion board. Then there are the credit-card sized modem, networking, and other adapters you can plug into your notebook's PC Card slot.

antenna gain - This describes an antenna's transmission power as a ratio of its output (send) signal strength to its input (receive) signal strength. It is usually expressed in dBi; a higher dBi means a stronger antenna.

AP - See access point.

ADSL - Asymmetric Digital Subscriber Line. ADSL uses standard phone lines to provide high-speed data communications. Although DSL comes in several flavors, when home users say they "get DSL," they really mean that an ordinary phone line is being conditioned for ADSL service. ADSL providers typically deliver upstream (from the user) speeds that top out at 128Kbps and downstream (to the user) speeds of no more than 1.5Mbps. Actual speeds may be much lower depending on the subscriber's physical distance from the telco switching station. ADSL supports simultaneous voice and data transmission, so a separate phone line is not required to obtain ADSL service.

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bandwidth - This term describes data-carrying capacity--in other words, how much (and how fast) data flows on a given transmission path. It can apply to network connections, system buses, or any "pipe" through which data pours. Bandwidth is commonly measured in bits or bytes per second. Low-bandwidth (dial-up modem) connections include rates of 56Kbps, while high-bandwidth (broadband) connections deliver more information at a much faster speed--making full-screen, full-motion video possible, for example.

Bluetooth - Bluetooth is a wireless computing and telecommunications specification that defines how mobile personal computing devices work with each other and with regular computer and phone systems within a close range. It uses the 2.4GHz band at 720Kbps within a 30-foot range. This technology is used with PANs as opposed to LANs.

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cable - A broadband transmission technology using coaxial cable or fiber-optic lines. First used for TV, it is now also being used for Internet access. Cable can transfer data downstream to your computer at speeds much faster than DSL can. The actual speed a user gets, however, depends on variables including the modem's throughput capability, the maximum throughput per user your cable service has set, and the number of other users sharing your neighborhood connection at any one time.

Cat-5 - Category 5 cabling is used in Ethernet and Fast Ethernet networks. It resembles a phone cable, but it's bigger, with four twisted-pair copper wires and a larger RJ-45 connector instead of an RJ-11.

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decibel - A mathematical ratio that indicates the relative strength of a device's electric or acoustic signal to that of another. It can be used by itself but is often paired with a specific unit of measure, such as a milliwatt (dBm) or an isotropic antenna (dBi). The higher a device's decibel rating, the more powerful its signal is.

dB – See decibel.

dBi - Decibels compared to an isotropic antenna. An antenna's gain is often measured in decibel strength compared to an isotropic antenna, a theoretical, perfect antenna whose range is 360 degrees in all directions. The higher the dBi, the stronger the antenna.

dBm - Decibels compared to one milliwatt. A wireless networking device's transmit and receive powers are often measured in decibel strength compared to one milliwatt of power. The higher the dBm, the greater the device's transmit or receive power.

directional antenna - This term defines several types of antennae that redirect the signal received from a transmitter to enhance its strength in a certain direction, unlike an omnidirectional antenna.

DSL - Digital Subscriber Line. Digital subscriber lines carry data at high speeds over standard telephone wires. DSL supports download speeds from 384Kbps to 1.5Mbps, depending on the quality of the lines and the distance your particular connection stretches from the telco switching station. The term xDSL is used to describe the many variations of DSL, such as ADSL and HDSL.

DSSS - Direct Sequence Spread Spectrum. DSSS is a spread spectrum radio technology. The sender alters, or modulates, the signal by spreading it over a wider frequency, generating what seems like signal noise to everyone except the receiver who knows how to return the signal to its original form, or demodulate it.

dual-band radio - A radio device is dual-band if it can send and receive signals from two frequencies.

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encryption - Encryption is the process of changing data into a form that can be read only by the intended receiver.

Ethernet - Ethernet is a standard for connecting computers into a local-area network (LAN). Ethernet is also called 10BaseT, which denotes a peak transmission speed of 10Mbps using copper twisted-pair cable.

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FCC - Federal Communications Commission. The government agency responsible for regulating telecommunications in the United States.

FHSS - Frequency Hopping Spread Spectrum. A type of spread spectrum radio technology where the sender and receiver "hop" together from one frequency to another to avoid detection or jamming.

firewall - A system that prevents unauthorized users from logging in to a private network (usually one that's connected to the public Internet). It can also be used to keep users inside the firewall from accessing computers outside the firewall.

fragment - In networking, a packet whose size exceeds the bandwidth of the network is broken into smaller pieces called fragments.

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gateway - A combination of a software program and piece of hardware that passes data between networks. In wireless networking, gateways can also serve as security and authentication devices, access points, and more.

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hot spot - In wireless networking, a hot spot is a specific part of an access point's range in which the general public can walk up and use the network. The service may be available only for a fee, and the hot spot's range is usually short to control the physical proximity of the user.

hub - This piece of networking hardware serves as a central connection point for multiple PCs or other devices (usually on a wired or wireless Ethernet network). A passive hub simply transmits data from any of its connected devices to the rest of the network. An active or manageable hub can also monitor network traffic and configure its ports.

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IEEE - Institute of Electrical and Electronics Engineers. Pronounced "eye-triple-E," this nonprofit U.S. engineering organization develops, promotes, and reviews standards within the electronics and computer science industries.

infrastructure mode - When a wireless network functions in infrastructure mode, every user communicates with the network and other users through an access point; this is the typical way corporate WLANs work. An alternative is ad-hoc mode, but users would have to switch to infrastructure mode to access a network's printers and servers.

ISM band - The 2.4GHz frequency spectrum is also known as the ISM band. ISM stands for Industrial, Scientific, and Medical, the noncommercial uses for which the 2.4GHz band and other frequencies were once reserved by the ITU-T.

ITU-T - International Telecommunications Union-Telecommunication.

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LAN - Local-Area Network. A local-area network is a short-distance network used to link a group of computers together, usually within a building. Ethernet is the most commonly used type of LAN. A piece of hardware called a hub serves as the common wiring point, enabling data to be sent from one machine to another over the network.

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Mbps - megabits per second. A megabit is roughly a million bits of data. This abbreviation is used to describe data transmission speeds. Several factors can influence how fast data travels, such as modem speed, bandwidth, and Internet traffic.

modem - An external box or internal circuitry that converts computer data into sound that can be transmitted over phone lines.

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NIC - Network Interface Card. An adapter inside a computer that lets the computer connect to a network via a wired or wireless transmission medium.

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OFDM - Orthogonal Frequency Division Multiplexing. A wireless transmission technique that splits a signal into smaller signals that are then transmitted at different frequencies simultaneously. It's the method employed for wireless transmissions that use the IEEE 802.11a and 802.11g specifications.

omnidirectional antenna - This is like a dipole antenna because it radiates its signal 360 degrees horizontally; however, its signal is flatter than a dipole's, allowing for higher gain.

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packet - While it may seem as though you send or receive a continuous stream of data every time you use the Internet, you don't. Instead, it's more efficient to break up the transmission into pieces called packets. These packets contain information about which computer sent the data and where the data is going. If a packet runs into a problem during its trip, it can attempt to find another route. When all the packets get where they're going, the recipient computer puts them together again.

PAN - Personal-Area Network. A PAN is distinct from a LAN because it's a casual, close-proximity network where connections are made temporarily.

PC Card - A credit card-size peripheral that plugs into a special slot on portable computers.

protocol - Because so many different types of computers and operating systems connect via modems or other connections, they have to follow communications standards called protocols.

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QoS - Quality of Service. QoS can be used to describe any number of ways in which a network provider guarantees a service's performance, such as an average or minimum throughput rate.

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RADIUS - Remote Authentication Dial-In User Service. The RADIUS is a server database used by an ISP to authenticate users who are trying to log on to the service. It can also track network usage.

RJ-11 - Registered Jack 11. This is the standard telephone connector.

RJ-45 - Registered Jack 45. RJ-45 connectors look a bit like standard phone connectors but are twice as wide. RJ-45s are used for hooking up computers to LANs or for phones with lots of lines.

router - Piece of hardware that routes data from one local-area network to another or to a phone line's long-distance line. Routers also act as controllers, allowing only authorized machines to transmit data into the local network so that private information can remain secure. In addition, routers handle errors, keep network usage statistics, and handle security issues.

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server - a server is usually a computer that provides the information, files, Web pages, and other services to the client that logs on to it.

spread spectrum - A wireless communications technology that scatters data transmissions across the available frequency band in a pseudorandom pattern. Spreading the data across the frequency spectrum greatly increases the bandwidth, it also makes the signal resistant to noise, interference, and snooping. Spread-spectrum modulation schemes are commonly used with personal communications devices such as digital cellular phones, as well as with WLANs and cable modems.

SSID - Service Set Identifier. Every wireless network or network subset has a unique identifier called an SSID. Every device connected to that part of the network uses the same SSID to identify itself as part of the “family, when it wants to gain access to the network or verify the origin of a data packet it's sending over the network.

switch - A device in a network that selects the path that a data packet will take to its next destination. The switch opens and closes the electrical circuit to determine whether--and where--data will flow.

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TCP/IP - Transmission Control Protocol/Internet Protocol. TCP/IP is the method by which data is sent across the Internet. These two protocols were developed by the U.S. military to allow computers to talk to each other over long-distance networks.

throughput - A general term used when defining how much data is going how quickly over a particular transport medium, such as a wireless network or a phone line.

twisted pair - Telephone companies commonly run twisted pairs of copper wires to each customer household. The pairs consist of two insulated copper wires twisted into a spiral pattern. Although originally designed for plain old telephone service (POTS), these wires can carry data as well as voice. New services such as ISDN and ADSL also use twisted-pair copper connections.

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VPN - Virtual Private Network. A private network of computers that's at least partially connected by public phone lines. A good example would be a private office LAN that allows users to log in remotely over the Internet. VPNs use encryption and secure protocols to ensure that data transmissions are not intercepted by unauthorized parties.

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WAN - Wide-Area Network. Wide-area networks can be made up of interconnected smaller networks spread throughout a building, a state, or the entire globe. The Internet could be considered a WAN. A wireless WAN is called a WLAN.

WEP - Wired Equivalent Privacy. All 802.11b networks use WEP as their basic security protocol.

Wi-Fi - Wireless Fidelity. Wi-Fi originally referred to the 802.11b specification for wireless LANs, but it is now used to describe any of the 802.11 wireless networking specifications.

wireless bridging - A networking bridge is used to connect two or more separate networks. A wireless bridge functions the same way but can be used in situations in which running a wire or cable would be impractical or prohibitively expensive.

wireless channel - Different networking technologies divide their allocated spectrum up in different ways. You can sometimes improve the performance of your network and avoid interference on the band by moving your network to a different nonoverlapping channel available to the devices. 802.11b and 802.11g devices have three nonoverlapping channels. 802.11a devices have eight nonoverlapping channels.

WLAN - Wireless Local-Area Network. A wirelessly connected LAN, such as an 802.11 network.

WPA - Wi-Fi protected access. WPA is a specification for improving the security of Wi-Fi networks, replacing the weaker WEP for current and future 802.11 standards.