code: function bytesToHexString(bytes) {
      var dec, hexstring, bytesAsHexString = "";
      for (var i = 0; i < bytes.length; i++) {
         if (bytes[i] >= 0) {
             dec = bytes[i];
         } else {
             dec = 256 + bytes[i];
         }
         hexstring = dec.toString(16);
         // zero padding
         if (hexstring.length == 1) {
             hexstring = "0" + hexstring;
         }
         bytesAsHexString += hexstring;
      }
      return bytesAsHexString;
  }
docs: useful for readable version of Tag UID