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rfid

Two RFID readers show different identifiers

I have used two RFID readers (different vendors), which provide two different identifiers for the very same RFID tag:

  • Reader A shows 5BFA0746 (decimal 1543112518)
  • Reader B shows 4607FA5B (decimal 1174927963)

Can you explain why? There are no similarities with the last bytes nor prefixes.

Solution

  • I'm not sure that I completely understand your question, but the two values are identical except for their byte-order. Hence, both readers do read the same value (possibly an ISO/IEC 14443-3 UID/anti-collsion identifier?). They just present them in reversed byte order:

              +--------+--------+--------+--------+
Reader A: | Byte 0 | Byte 1 | Byte 2 | Byte 3 |
          |   5B   |   FA   |   07   |   46   |
          +--------+--------+--------+--------+
Reader B: | Byte 3 | Byte 2 | Byte 1 | Byte 0 |
          |   46   |   07   |   FA   |   5B   |
          +--------+--------+--------+--------+