Wiegand White Paper

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1、TechnologyBasics:UnderstandingWiegand·AbriefhistoryofWiegandcardsandreaders.·TheWiegandreader-to-controllercommunicationprotocol.·Thecontroller’sabilitytoreceiveandinterpretthecarddata.TechnologyBasics:UnderstandingWiegand©2004HIDCorporation.Allrightsreserved.TableofContentsTableofIllustrations2U

2、nderstandingWiegand™3SeeSummaryonP.5fortheimportanceofWiegandtoHID3ALittleHistory3TheCard3TheReader4TheWiegandProtocol5HIDandWiegand5HIDownswhatwasknownasSensorEngineering.5HIDProx(125kHz)andiCLASSreadersusetheWiegandreader-to-controllerprotocol.5AllHIDCardscanbemadewithanycarddataFormat.5AnAcces

3、sControlPanelcan’tdistinguishbetweentheoutputfromWiegand,125kHzandiCLASSreaders.5TableofIllustrationsFigure1:TheWiegandCard3Figure2:ATypicalHIDWiegandReader4TechnologyBasics:UnderstandingWiegand©2004HIDCorporation.Allrightsreserved.UnderstandingWiegand™ThetermWiegandisappliedtoseveralcharacterist

4、icsrelatedtoAccessControlreadersandcards.Unfortunately,thewordisusedverycarelesslyandcanleadtounnecessaryconfusion.Herearethebasicfacts.Wiegandis:1.Aspecific“Swipe”technologyReader-to-CardInterface2.Aspecificthree-wirecurrentpulseReader-to-ControllerInterface3.The"Standard”26bitbinaryCarddataForm

5、at4.Anelectromagneticeffect5.AcardtechnologyForthisdiscussion,weareparticularlyinterestedinthefirsttwoitems.AseparateHIDWhitePaperdiscussestheFormatsusedforcarddataindetail.SeeSummaryonP.5fortheimportanceofWiegandtoHIDALittleHistoryIntheearly1970s,JohnWieganddevelopedanew,superiortechnologyforenc

6、odingbinarydataonacardandreadingitwithareader.Priortohisinventions,mostcardsusedeitheramagneticstripe(stillusedtoday)oranimbeddedpatchofbarium-ferrite(obsolete)tocontainabinarycardnumber.Bothtechnologiessufferedfromrapidreaderandcardwearandfrequentcardholderinconvenience.TheWiegandtechnologiesrad

7、icallyimprovedthereliabilityandlifespanofboththereaderandthecard.TheCardFigure1:TheWiegandCardTechnologyBasics:UnderstandingWiegand©2004HIDCorporation.Allrightsreserved.ThesecretoftheWiegandcardistheuseoftworowsoftiny,