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<html> <head> <title>RFID-Bulletin Board: Re: ISO 14443, type A or type B?, Klaus Finkenzeller at 7/22/2000 21:26</title> <!-- Anfang Header --><!-- Ende Header --> </head> <BODY BGCOLOR="#fffcf4"><!-- Anfang BeitragsseitenKopf --><!-- Ende BeitragsseitenKopf --><!-- AnfangBanner --><!-- EndeBanner --><blockquote> <center> <h1>Re: ISO 14443, type A or type B?</h1> </center><!-- Anfang BeitragsNavigationsLeisteOben --><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><center><P><B>[ <a href="../index.htm">RFID-Bulletin Board</a> ]</B></P></center><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><!-- Ende BeitragsNavigationsLeisteOben --><p>Written by <a href="mailto:klaus.finkenzeller@web.de">Klaus Finkenzeller</a> at 22 Jul 2000 21:26:23:<p>As an answer to: <a href="124.htm">ISO 14443, type A or type B?</a> written by Tommy Jackson at 22 Jul 2000 17:47:54:<p>>Hello everybody, i would like to know that, if i place a conactless less smart card to the reader, how does the reader know that the card is type A or type B? By the way, where have the information about the RF interface of the ISO 14443? <p>Dear Tommy,<p>as you might know, the difference between type A and type B of ISO 14443 is the modulation and coding at the RF-interface between card and reader (Type A: 100% ASK, modified miller code. Type B: 10% ASK with NRZ-coding). A type B card placed in the interrogation zone of a reader therefore does not recognize anny transmission with type A modulation. Also a type A card does not recognize any type B transmission of a reader.<br>A reader waiting for any card entering the interrogation zone is in the polling-state. In this state, the reader will permanently transmitt a Request-command, which will be answered by any card, as soon as being powered up after entering the interrogation zone. An ISO 14443 reader now, hast to switch permanently between type A and B and send a corresponding Request-command in every mode.<br>The Request-command sequence looks like this: <br>REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - ....<br>If either a type A or a type B card will anser a correspondting request command (just after having entered the interrogatin zone), the reader knows that there is at least one card in the field and starts the communication with this card (anticollission, select, transaction, ...), using the modulation type of the request command, the card has been answered to. Thats all about indicating the type of the card!!! <br>After having finished that transaction the card will be set into a HALT-mode and the request-sequence be restarted again.<p>If you are able to read German language, you will find a more detailed description of the type A and B-interface in the 2nd edditon of the RFID-handbook, but unfortunately this is not yet available in the 1st english eddition.<p>With best regards,<br>Klaus<p><br><br><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><form method=POST action="http://f16.parsimony.net/forum26490/wwwforum.cgi?formular"><input type=hidden name="followup" value="124,126"><input type=hidden name="origname" value="Klaus Finkenzeller"><input type=hidden name="origemail" value="klaus.finkenzeller@web.de"><input type=hidden name="origsubject" value="Re: ISO 14443, type A or type B?"><input type=hidden name="origdate" value="22 Jul 2000 21:26:23"><input type=hidden name="subject" value="Re: ISO 14443, type A or type B?"><input type=hidden name="body" value=">>Hello everybody, i would like to know that, if i place a conactless less smart card to the reader, how does the reader know that the card is type A or type B? By the way, where have the information about the RF interface of the ISO 14443? >Dear Tommy,>as you might know, the difference between type A and type B of ISO 14443 is the modulation and coding at the RF-interface between card and reader (Type A: 100% ASK, modified miller code. Type B: 10% ASK with NRZ-coding). A type B card placed in the interrogation zone of a reader therefore does not recognize anny transmission with type A modulation. Also a type A card does not recognize any type B transmission of a reader.>A reader waiting for any card entering the interrogation zone is in the polling-state. In this state, the reader will permanently transmitt a Request-command, which will be answered by any card, as soon as being powered up after entering the interrogation zone. An ISO 14443 reader now, hast to switch permanently between type A and B and send a corresponding Request-command in every mode.>The Request-command sequence looks like this: >REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - REQA(100%ASK) - REQB(10%ASK) - ....>If either a type A or a type B card will anser a correspondting request command (just after having entered the interrogatin zone), the reader knows that there is at least one card in the field and starts the communication with this card (anticollission, select, transaction, ...), using the modulation type of the request command, the card has been answered to. Thats all about indicating the type of the card!!! >After having finished that transaction the card will be set into a HALT-mode and the request-sequence be restarted again.>If you are able to read German language, you will find a more detailed description of the type A and B-interface in the 2nd edditon of the RFID-handbook, but unfortunately this is not yet available in the 1st english eddition.>With best regards,>Klaus"><input type="submit" name="abschicken" value="Write an answer"> <br><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><p><a name="followups"><B>Answers:</B></a><br><ul><!--insert: 126--></ul><!--end: 126--><!-- Anfang BeitragsNavigationsLeisteUnten --><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><center><P><B>[ <a href="../index.htm">RFID-Bulletin Board</a> ]</B></P></center><!-- AnfangLinie --><center><p><HR></p></center><!-- EndeLinie --><!-- Ende BeitragsNavigationsLeisteUnten --></blockquote><!-- Anfang BeitragsseitenFuss --><!-- Ende BeitragsseitenFuss --></body></html>⌨️ 快捷键说明
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