Telephone card
A telephone card, calling card or phone card for short, is a small plastic card, sized and shaped like a credit card
Credit card
A credit card is a small plastic card issued to users as a system of payment. It allows its holder to buy goods and services based on the holder's promise to pay for these goods and services...

, used to pay for telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

 services. It is not necessary to have the physical card except with a stored-value system; knowledge of the access telephone number to dial and the PIN is sufficient. Standard cards which can be purchased and used without any sort of account facility give a fixed amount of credit and are discarded when used up; rechargeable cards
Rechargeable calling card
A rechargeable calling card is a type of telephone card that the user can "recharge" or "top up" by adding money when the balance is low. Introduced in the early 1990s the rechargeable calling card has become the most common telephone card available after the original calling card was introduced...

 can be topped up, or collect payment in arrears
Arrears is a legal term for the part of a debt that is overdue after missing one or more required payments. The amount of the arrears is the amount accrued from the date on which the first missed payment was due...