Offline debit transactions take place using the dual message credit card processing method in which the authorization occurs at the time of the transaction using one message, and the transaction is settled later using another message. These transactions do not require a PIN (Personal Identification Number), but do require the cardholder's signature. This transaction is processed like a credit card with the posting to the cardholder's account within a few days of the transaction occurrence. These are often referred to as 'check card' or 'debit card' transactions.

Sale inputted to terminal for a voice authorization

An online debit transaction occurs in a single message format that allows the transactions to be completely settled from an authorization request. This method requires a cardholder to enter their PIN (Personal Identification Number). The transaction must be approved online by requesting authorization from the financial institution. If the transaction is approved, funds are withdrawn from the cardholder's account at the time of the transaction. The funds for the transaction are guaranteed to the merchant.