AUC Decoder
Decode the EMV Application Usage Control (tag 9F07) bitfield — the issuer's rules for where and how the card may be used.
What the Application Usage Control (9F07) restricts
The Application Usage Control (AUC), EMV tag 9F07, is a 2-byte bitmap of issuer rules describing where and how a card may be used. The issuer personalises it onto the card, and the terminal checks it during processing to decide whether the transaction type and location are permitted — for example, blocking an ATM withdrawal on a card issued for purchases only, or refusing an international transaction on a domestic-only product.
Reading the flags
The bits split into pairs of "valid for domestic / valid for international": cash, goods, services, and ATMs, plus "valid at terminals other than ATMs" and domestic/international cashback. The terminal compares the AUC against its own terminal type and the terminal/issuer country codes. A mismatch — say, AUC permits domestic cash only while the terminal country differs from the issuer country — causes the terminal to set the corresponding "service not allowed" bit in the TVR, which is a frequent root cause of otherwise puzzling declines.
Common questions
A cash withdrawal was declined but purchases work — why?
The AUC most likely has the cash bits clear. The card simply is not authorised for cash access, independent of balance or limits.
Does the AUC stop a transaction on its own?
Indirectly. The AUC drives a TVR flag; the actual accept/decline then comes from comparing the TVR against the terminal and issuer action codes.
Bit definitions follow EMV Book 3. All checks run locally in your browser.