Forum › MIFARE general topics and applications › old reader with new desfire cards › Reply To: old reader with new desfire cards
Hi Andreas,
the UID is used in the anti-collision loop. Yes, older MIFARE Classic cards uses 4 byte UID. But the space for 4 byte UIDs is exhausted, therefore all new MIFARE cards uses 7 byte UID.
This approach is not very robust. Why you do not personalize the card with 16 byte data block (in case of a Classic)? Then the card UID is needless and you can ignore the UID completely.
Please take in mind, MIFARE DESFire cards can be configured to use a random UID in the anti-collision loop. Then your approach to track a card will not work.
How the anti-collision is implemented, depends on the reader manufacturer’s software. I recommend to get the user manual of your reader.
The TapLinx team
the UID is used in the anti-collision loop. Yes, older MIFARE Classic cards uses 4 byte UID. But the space for 4 byte UIDs is exhausted, therefore all new MIFARE cards uses 7 byte UID.
This approach is not very robust. Why you do not personalize the card with 16 byte data block (in case of a Classic)? Then the card UID is needless and you can ignore the UID completely.
Please take in mind, MIFARE DESFire cards can be configured to use a random UID in the anti-collision loop. Then your approach to track a card will not work.
How the anti-collision is implemented, depends on the reader manufacturer’s software. I recommend to get the user manual of your reader.
The TapLinx team
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