Definition
Dial-upisthemethodandprocessofusingtelephonelinestoconnecttotheInternet.
Inordertousethedial-upmethodtoconnecttotheInternet,thehardwaredevicethatneedstobeequippedisamodem,whichisusedtoconvertthedigitalsignalofthecomputerandtheanalogsignalofthetelephoneline.Aftertheuserusesamodemtoconnecthiscomputertothetelephoneline,hedialsatelephonenumbertotheremotehosttoestablishaconnectionwiththehost.
Duringthephonedialingprocess,dialingreferstodialingthenumbersonthedialpadaccordingtothephonenumber.
Dialingmethod
Thedialingmethodisawayforuserstodialadecimalnumbertomakelocalcalls,domesticlong-distancecalls,andinternationallong-distancecalls.ThedialingmethodofGSMmobilecommunicationstipulatedbythetechnicalsystemofChina'smobilecommunicationnetworkis(takeChinaMobileNetworkasanexample):
Mobileuser-fixeduser(includinganalogmobileuser)0XYZPQRABCD;
Fixeduser-localmobileuser139ABCD;
Fixeduser-non-localmobileuser0139ABCD;
Mobileuser-mobileuser139ABCD;
Mobileuser-specialserviceserviceOXYZlXX,inwhichyouonlyneedtodial119forfirealarm,110forpolice,and120foremergencycenter,Tothetrafficpolicecenteronlyneedtodial122;
Internationaluser-mobileuserinternationallongdistancerightprefix+139ABCD;
Mobileuser-internationaluser00+Countrycode+Avalidphonenumberinthecountry.Amongthem
0——Domesticlong-distanceauthorizedprefix;
00——Internationallong-distanceauthorizedprefix;
XYZ——long-distanceareacode,whichis3Digitsor2digits;
PQR——officenumber;
ABCD——usernumber,whenthelongdistanceareacodeis2digits,theusernumbercanconsistof4or5digitsNumbercomposition;
LXX——specialservicenumber.
BecausethenetworkaccessnumberoftheGSMmobilecommunicationnetworkis"139","139"notonlyhasthecharacteristicsofaspecialservicenumber,butalsohasthecharacteristicsofalong-distanceareacode.Becausebothinternationalanddomesticlongdistancesareanalyzed"139"andthenconnectedtoChinaMobile'sGSMmobilecommunicationnetwork.
Accordingtothetechnicalsystemofmycountry’stelephonenetwork,thedialingmethodisalockeddialingmethod,thatis,whenuserscalleachotherinalockednumberingarea(along-distancenumberingareaisalockednumberingarea),thereisnoneedtodialLong-distanceareacode,andwhenusersintwolocked-numberedareascalleachother,theymustdialthelong-distanceareacodeofthecalledlockedarea.
Therefore,whenamobileusercallsafixedtelephonenetworkuser,usersintwolockednumberingareascommunicatewitheachother.Themobileuserneedstodialthelong-distanceareacodewherethecalledfixeduserislocated.
Conversely,whenafixeduser(includingananalogmobileuser)callsamobileuser,thetwointerlockeduserscancommunicatewitheachother.Thefixedusershoulddialthemobileuser’s"long-distanceareacode"139,butbeforethelong-distanceareacodeYouneedtoaddthelongdistanceprefix"0"toknowthatthenumberafterthe"0"isthelongdistanceareacode.
Inthisway,aproblemarises,thatis,whereverafixedusercalls,amobileusermustfirstdial"0139".Limitedtothelargenumberoffixedusersonthepublictelephonenetworkinmycountry,theyarealsonon-long-distanceauthorizedusers.Thebusinesslocalnetworkisthesameasthefixedtelephonelocalnetwork.Therefore,non-long-distanceauthorizedfixeduserscancalllocalfixedtelephoneusersbutcannotcallmobileusersofthelocalGSMmobilecommunicationnetwork.Thisisobviouslyunreasonable,anditwillbringtothetelecommunicationsbureau.Thereisabigbusinessloss.ABCD,atthistime139hasthespecialservicenumbercharacteristics;whencallingmobileusersoutsideofthecountry,thelongdistanceprefix"0"mustbedialedbefore139,atthistime139hasthelongdistanceareacodecharacteristics.
Dial-upprocess
Figure1Dial-upprocess(7photos)
Createadial-upnetwork,enterInternetaccountconnectioninformation;Configuredial-upNetwork,selectTCP/IPprotocol;
ConfigureTCP/IP,dial-upconnection;
Thedial-upprocessisshowninFigure1ontheright.