ADSL(AsymmetricDigitalSubscriberLine)technologyisanasymmetricdigitalsubscriberlinetechnologytoachievebroadbandaccesstotheInternet.Asatransmissionlayertechnology,ADSLmakesfulluseoftheexistingcopperwireresources.Thetwistedpaircableprovidesanuplinkbandwidthof640kbps(theoreticaluplink1Mbps)andadownlink8Mbpsbandwidth,therebyovercomingthe"bottleneck"oftraditionalusersinthe"lastmile"andrealizingbroadbandaccessinthetruesense.
Upstreamspeedgenerallyreferstotheuploadspeedfromyourcomputer,thatis,thespeedatwhichotherscommunicatefromyourcomputer.
Generally,theuplinkanddownlinkratesofADSLInternetaccessareasymmetrical,whichmeansthattheuplinkrateisdifferentfromthedownlinkrate.Now1Misgenerallyuplink:386Kbit,downlink:1024Kbit,2Muplink:386Kbit,downlink:2048Kbit
Note:bitisabitandbyteisabyte,andthedownloadspeedgenerallyreferstoabyte.The2Mbandwidthmentionedbythetelecommunicationscompanyactuallyreferstobits(bit)ratherthanbytes(byte)
Theactualdownloadspeedshouldbecalculatedaccordingtothisformula:8bit(bit)=1byte(byte),Forexample,ifyoudoa2Mbroadband,2Mbit(bit)=2048Kbit(bit),2048/8=256kbyte(byte),becauseourcomputerdefinesthefilesizeunitbydefaultisbyte(byte),soourdownloadspeedGenerallyreferstobytes(byte)ratherthanbits(bit),soouractualdownloadspeedisequaltobandwidthdividedby8.