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ASUS WLAN Card
Chapter 5
Chapter 5 - Glossary
Glossary
Each subchannel in the COFDM implementation is about 300 KHz wide. At the low
end of the speed gradient, BPSK (binary phase shift keying) is used to encode 125
Kbps of data per channel, resulting in a 6,000-Kbps, or 6 Mbps, data rate. Using
quadrature phase shift keying, you can double the amount of data encoded to 250 Kbps
per channel, yielding a 12-Mbps data rate. And by using 16-level quadrature amplitude
modulation encoding 4 bits per hertz, you can achieve a data rate of 24 Mbps. The
802.11a/g standard specifies that all 802.11a/g-compliant products must support these
basic data rates. The standard also lets the vendor extend the modulation scheme beyond
24 Mbps. Remember, the more bits per cycle (hertz) that are encoded, the more
susceptible the signal will be to interference and fading, and ultimately, the shorter the
range, unless power output is increased.
Default Key
This option allows you to select the default WEP key. This option allows you
to use WEP keys without having to remember or write them down. The WEP
keys generated using the Pass Phrase is compatible with other WLAN products.
The Pass Phrase option is not as secure as manual assignment.
Device Name
Also known as DHCP client ID or network name. Sometimes provided by an
ISP when using DHCP to assign addresses.
DHCP (Dynamic Host Configuration Protocol)
This protocol allows a computer (or many computers on your network) to be
automatically assigned a single IP address from a DHCP server.
DNS Server Address (Domain Name System)
DNS allows Internet host computers to have a domain name and one or more IP
addresses. A DNS server keeps a database of host computers and their respective domain
names and IP addresses, so that when a user enters a domain name into the Internet
browser, the user is sent to the proper IP address. The DNS server address used by the
computers on your home network is the location of the DNS server your ISP has assigned.
DSL Modem (Digital Subscriber Line)
A DSL modem uses your existing phone lines to transmit data at high speeds.
Direct-Sequence Spread Spectrum (for 802.11b)
Spread spectrum (broadband) uses a narrowband signal to spread the transmission over
a segment of the radio frequency band or spectrum. Direct-sequence is a spread spectrum
technique where the transmitted signal is spread over a particular frequency range.
Direct-sequence systems communicate by continuously transmitting a redundant pattern
of bits called a chipping sequence. Each bit of transmitted data is mapped into chips
and rearranged into a pseudorandom spreading code to form the chipping sequence.
The chipping sequence is combined with a transmitted data stream to produce the
output signal.
