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telephone network, or Plain Old Telephone Service
(POTS).
DNS
Domain Name Service A program that translates
URLs to IP addresses by accessing a database
maintained on a collection of Internet servers. The
program works behind the scenes to facilitate
surfing the Web with alpha versus numeric
addresses. A DNS server converts a name like
mywebsite.com to a series of numbers like
107.22.55.26. Every website has its own specific IP
address on the Internet.
DSL
Digital Subscriber Line Various technology
protocols for high-speed data, voice and video
transmission over ordinary twisted-pair copper
POTS (Plain Old Telephone Service) telephone
wires.
Encryption key
An alphanumeric (letters and/or numbers) series
that enables data to be encrypted and then
decrypted so it can be safely shared among
members of a network. WEP uses an encryption
key that automatically encrypts outgoing wireless
data. On the receiving side, the same encryption
key enables the computer to automatically decrypt
the information so it can be read. Encryption keys
should be kept secret
Firewall
A device or computer program that keeps
unauthorized users out of a private network.
Everything entering or leaving a system's internal
network passes through the firewall and must meet
the system's security standards in order to be
transmitted. Often used to keep unauthorized
people from using systems connected to the
Internet.
Hub
A multiport device used to connect PCs to a
network via Ethernet cabling or via 802.11. Wired
hubs can have numerous ports and can transmit
data at speeds ranging from 10 Mbps to multi-
Gigabyte speeds per second. A hub transmits
packets it receives to all the connected ports. A
small wired hub may only connect 4 computers; a
large hub can connect 48 or more.
Hz
Hertz. The international unit for measuring
frequency, equivalent to the older unit of cycles per
second. One megahertz (MHz) is one million hertz.
One gigahertz (GHz) is one billion hertz. The
standard US electrical power frequency is 60 Hz,
the AM broadcast radio frequency band is 535—
1605 kHz, the FM broadcast radio frequency band
is 88—108 MHz, and wireless 802.11b/g LANs
operate at 2.4 GHz.
IEEE
Institute of Electrical and Electronics Engineers,
New York, www.ieee.org. A membership
organization that includes engineers, scientists and
students in electronics and allied fields. It has more
than 300,000 members and is involved with setting
standards for computers and communications.
Infrastructure mode
An 802.11 setting providing connectivity to an AP.
As compared to Ad-Hoc mode, whereby 802.11
devices communicate directly with each other,
clients set in Infrastructure Mode all pass data
through a central AP. The AP not only mediates
wireless network traffic in the immediate
neighbourhood, but also provides communication
with the wired network. See Ad-Hoc and AP.
I/O
Input / Output. The term used to describe any
operation, program or device that transfers data to
or from a computer.
Internet appliance
A computer that is intended primarily for Internet
access is simple to set up and usually does not
support installation of third-party software. These
computers generally offer customized web
browsing, touch-screen navigation, e-mail services,
entertainment and personal information
management applications.
IP
Internet Protocol. A set of rules used to send and
receive messages across local networks and the
Internet.
IP telephony
Technology that supports voice, data and video
transmission via IP-based LANs, WANs, and the
Internet. This includes VoIP (Voice over IP).
IP address
A 32-bit number that identifies each sender or
receiver of information that is sent across the
Internet. An IP address has two parts: an identifier
of a particular network on the Internet and an
identifier of the particular device (which can be a
