title: NFC tags unique ID
body: <p>I'm developing a system including NFC tags and Android phone , using unique ID of NFC tags . 
  But don't know what is the differences between 4 types NFC tag . 
  I've found this : </p>
  
  <blockquote>
    <p>"NFC-compatible tags can be of the following technologies/standards
    and each of them has a different notion of ID:</p>
  </blockquote>
  
  <pre><code>NFC Tag1 : Topaz/Jewel
  NFC Tag2 : Mifare UL (ISO14443A-3)
  NFC Tag3 : JIS X 6319-4 (FeliCa)
  NFC Tag4 : ISO14443-4A or ISO14443-4B tag
  </code></pre>
  
  <p>There is also an unofficial support of the Mifare Classic cards as NFC tags.
  And each of them define some identification number.</p>
  
  <ul>
  <li>Topaz/jewel has a 4-byte ID</li>
  <li>Mifare UL has a 7-byte UID</li>
  <li>Mifare Classic has a 4 or 7-byte UID</li>
  <li>FeliCa has a 8-byte ID</li>
  <li>ISO14443-4A has a 4, 7 or 11-byte UID</li>
  <li>ISO14443-4B has a 4-byte PUPI</li>
  </ul>
  
  <p>Do some tests with nfc-list, you'll see what comes out depending on the used tag.
  And for code, see code of nfc-list.c how IDs are retrieved and displayed."</p>
  
  <p>Is that true and is thera anything else ?
  Can you help me ?</p>