How They Work _

In Spain, whenever you make a payment or a cash withdrawal, the merchant's terminal or the ATM requests authorization on line (in real time) from your issuing institution via a complex communications system. The institution's server will verify your bank account or credit balance. If the request is accepted, the transaction will be authorized and the amount will be deducted from your balance.

In the rest of the world, the transaction may also take place in real time, but in some countries it may take place off line.