I have around 10k+ devices, each with both a visible serial number printed on a label and a RFID tag from which the serial number can be read as well. My problem is that when I read a RFID tag I get a bunch of hexadecimal values and I am unable to retrieve the actual serial number value from them as it is not a straightforward decimal to hex encoding.
Here are a couple of information that I get when scanning the RFID tag with the Android App "NFC Tools":
- Tag Type: ISO 15693 NXP - ICODE SLIX
- Technology available: NfcV, Ndef
- Serial number: 3C:FB:88:14:50:01:04:E0
- DSFID: 0x00
- Data format: Unknown
- Size: 38 / 106 Bytes
- Writable: Yes
- Can be made Read-only: No
I have noticed that each and every RFID tag contains the same 'header' 50:01:04:E0, so it means there should exist a way to retrieve my serial number from 3C:FB:88:14. In this particular instance, the serial number is 11926214.
I have scanned about 30 units manually, but I would like to avoid having to scan all 10,000 as it is error prone to write down the hex values and the corresponding serial. Is it possible at all with the above information to figure it out ?
Section 9.2.1 of the datasheet for the chip might help https://www.nxp.com/docs/en/data-sheet/SL2S2002_SL2S2102.pdf
Some App's might show the most significant bit first as it seems with this app (i.e. in reverse to the more normal orientation)
That actually puts 3C:FB:88:14:50 as the IC manufacturer serial number
or 50:14:88:FB:3C as the manufacturer defines it.
I've tried various Hex to Decimal converts like https://www.rapidtables.com/convert/number/hex-to-decimal.html and cannot get any combination and significant bit orientation to convert to the make the device serial number.
These chips also have user defined memory that App's has not been read and the Device Serial could be stored in here and not related to the Tag's serial number. (As the RFID serial is programmed by NXP at manufacture time it is unlikely to also be the devices serial number)
I suggest actually using the App TagInfo by NXP as this is by the Manufacturers of the Chip and can show you the all the raw memory blocks (It can on the card type I use)
BUT it seems that NXP have removed the TagInfo App very recently :-(
Update: Seems you might be able to side load the APK from https://apkpure.com/nfc-taginfo-by-nxp/com.nxp.taginfolite (with the associated risks)
Of course you can use the linked datasheet to write your own App to read the user memory area where the Device Serial might be stored.