7
1 Introduction
Thischapterdescribesthe packagecontentsand providesalist offeaturesand
application illustrationsof theADSLWireless Router.
1.1AbouttheADSL WirelessRouter
DSL(DigitalSubscriberLine)referstoatechnologyused toincreasethe datacapacity
of standardtwisted-pairwiresthat aregenerallyusedtoconnect mosthouseholdsto
the phonenetwork. Inaddition, thistechnologyallowssimultaneousvoiceand
high-speeddatatransmission overasinglepairoftelephonewires.
ThereareseveralkindsofDSLservices, eachwithitsowncompromisesbetween
speed,distance, cost, and reliability.Theseservicesareeithersymmetrical(data
flowsatthe samespeed inbothdirections), orasymmetrical(the downstream
capacityishigherthan theupstreamcapacity).
ADSL
AsymmetricDigitalSubscriberLine (ADSL),asitsnameindicates,isan asymmetrical
datatransmission technologywhichprovideshigh-speeddatatransferoverexisting
telephone orISDN linesbymaking gooduseofthe previouslyunused high-frequency
band-width.ADSLprovidesmuchhigherdownstreamspeed than upstreamspeed. It
ismuchpopularasordinaryusersdownloadmuchmoredatathan what theyupload.
ADSLprovidesadedicatedsecurecommunication between you and the ISP(Internet
ServiceProvider) and theconnectionishigh-speed and always-on.
Ethernet/ FastEthernet/ USB
Ethernet isthe most widely-usednetworkaccess method, especiallyinaLocalArea
Network(LAN)and isdefinedbythe IEEE 802.3standard. Normally, Ethernet isa
shared mediaLAN.All stationsonthesegmentsharethetotalbandwidth, whichcould
be 10Mbps(Ethernet), 100Mbps(Fast Ethernet), or1000Mbps(Gigabit Ethernet).
WithaswitchedEthernet, eachsenderandreceiverhasthefull bandwidth.
Fast Ethernet isdefined asIEEE 802.3u standard, ahigh-speedversion of Ethernet
with100Mbpstransmission rate.
USB (UniversalSerialBus)isadatacommunicationstandardwhichallowsthe
PC/desktoptodetectnewdevicessuchasprinters, joysticks, keyboards, mice,
adapters, storagedevices,audiodevices,digitalcamerasand thingswiththis
technology.Theadvantage of USB istoreplacedifferent typesofserialandparallel
port connectorswithonestandardized plug and portcombination withthe data
transferrateupto12Mbps.Alsolow-powerdevicescan drawpowerfromUSB and
dont requirean extraadapter. Beforeyou usethisconnector, you mayneed toinstall
the USB driverfirst.
Wireless LAN
Wireless LocalArea Networksystems(WLANs)transmitand receivedataoverthe air
byusing radiofrequency (RF).Thisofferssomeadvantageslikemobility, easeof
installation, andscalabilityovertraditionalwired systems.