It is the information printed on a card's Track 1 and Track 2 data, which holds information such as the card type, PIN usage status, domestic/international usage status, etc.
The service code information for cards is kept at the product level in bank systems. All cards under a given product are expected to be printed with the same service code.
POS device versions developed in recent years generally act according to the service code on the card to decide on the Prompt/Do Not Prompt PIN action.
In transactions made by reading the magnetic stripe on a POS, the POS behaves according to the service code. In transactions made by reading the chip, the transaction is not processed based on the service code.
In Turkiye, the service code value for standard MasterCard- and Visa-branded cards is generally printed as 126, and an online PIN is requested during transactions.
If we break down the value 126 according to the table below;
1: International Card
2: Positive Online Authorization Required
6: Prompt for PIN if PIN Pad Present—Goods and services only at Point of Sale (no cashback)
Note: Troy cards without Discover support are printed with the service code 526, since they cannot yet be used abroad.
