1 Reply Latest reply on Apr 11, 2012 10:27 PM by Sebastien_Lorquet

    what is atr header?


      I've read several documents about ATR and I found that before I get ATR, there is another four bytes which called ATR header, so I'm curious how can I get this ATR header?

      many thanks for your attention
        • 1. Re: what is atr header?
          I'm curious about your documents !?

          Please RTFISO7816-3

          There is no such thing as an atr header

          the atr is the string of the first bytes emitted by a contact card following an activation sequence. In an ATR, you have a variable number of interface bytes, then a variable number of historical bytes.

          contactless cards don't have ATRs.

          ISO 14443-B cards have a PUPI (4 bytes)
          ISO 14443-A cards have an UID (4,7 or 10 bytes)

          this value is exchanged before the reader reports a fake-ATR.