Card Application Selection is the process where the Payment Terminal (POI) chooses one application (AID - Application Identifier) from the multiple applications stored on a chip card to handle the transaction. This occurs immediately after the card is presented but before the host authorization request.
This functionality is mandatory when a card contains applications from different schemes (e.g., a card with both an international and a domestic scheme).
How Application Selection Works
The selection process is governed by rules pre-loaded into the terminal, ensuring the transaction is routed using the preferred method.
Card Presentation
When a chip card is inserted or tapped, the terminal reads the list of AIDs available on the card.
Default priority
The terminal compares the list of card AIDs with its internal list of supported AIDs. It then select by default an application based on configured a priority preference list.
If the terminal finds multiple applications that are both supported and have the same priority level, the terminal will offer the customer a choice. The customer is prompted to select which application they want to use for the purchase (e.g., "Press 1 for Debit, Press 2 for Credit").
Customer Choice
Customers can also force application selection by clicking on the schemes logo before tapping the card. When the customer will present its card, POI will allow them to select the application, regardless of the technology used for the payment (Chip, Contactless...).