Payment cards are part of a payment system issued by financial institutions, such as a bank, to a customer that enables its owner (the cardholder) to access the funds in the customer's designated bank accounts, or through a credit account and make payments by electronic funds transfer and access automated teller machines (ATMs). Such cards are known by a variety of names including bank cards, ATM cards, MAC (money access cards), client cards, key cards or cash cards.
There are a number of types of payment cards, the most common being credit cards and debit cards. Most commonly, a payment card is electronically linked to an account or accounts belonging to the cardholder. These accounts may be deposit accounts or loan or credit accounts, and the card is a means of authenticating the cardholder. However, stored-value cards store money on the card itself and are not necessarily linked to an account at a financial institution.
It can also be a smart card that contains a unique card number and some security information such as an expiration date or CVVC (CVV) or with a magnetic strip on the back enabling various machines to read and access information. Depending on the issuing bank and the preferences of the client, this may allow the card to be used as an ATM card, enabling transactions at automatic teller machines; or as a debit card, linked to the client's bank account and able to be used for making purchases at the point of sale; or as a credit card attached to a revolving credit line supplied by the bank.
Most payment cards, such as debit and credit cards can also function as ATM cards, although ATM-only cards are also available. Charge and proprietary cards cannot be used as ATM cards. The use of a credit card to withdraw cash at an ATM is treated differently to a POS transaction, usually attracting interest charges from the date of the cash withdrawal. Interbank networks allow the use of ATM cards at ATMs of private operators and financial institutions other than those of the institution that issued the cards.
All ATM machines, at a minimum, will permit cash withdrawals of customers of the machine's owner (if a bank-operated machine) and for cards that are affiliated with any ATM network the machine is also affiliated. They will report the amount of the withdrawal and any fees charged by the machine on the receipt. Most banks and credit unions will permit routine account-related banking transactions at the bank's own ATM, including deposits, checking the balance of an account, and transferring money between accounts. Some may provide additional services, such as selling postage stamps.
For other types of transactions through telephone or online banking, this may be performed with an ATM card without in-person authentication. This includes account balance inquiries, electronic bill payments, or in some cases, online purchases (see Interac Online).
ATM cards can also be used on improvised ATMs such as "mini ATMs", merchants' card terminals that deliver ATM features without any cash drawer. These terminals can also be used as cashless scrip ATMs by cashing the receipts they issue at the merchant's point of sale.