Overview#AID or Application Identifiers are defined within ISO 7816.
AID are data labels that differentiates payment systems and products.
The Card Issuer uses the AID to identify an application on the card or POS Terminal. Cards and terminals use AID to determine which applications are mutually supported, as both the card and the terminal must support the same AID to initiate a transaction.
Both cards and terminals may support multiple AIDs.
An AID consists of two components: