A telephone car, calling card or phone card for short, is a small card, usually resembling a credit card, used to pay for telephone services. Such cards can either employ prepaid credit system or credit card style system of credit. The exact system for payment, and the way in which the card is used to place a telephone call, depend on the overall telecommunication system. Currently, the most common types of telephone cards involve pre-paid credit in which the card is purchased with a specific balance, from which the cost of calls made is deducted. Pre-paid phone cards are disposable. When the balance is exhausted you simply buy a new card. Cards purchased can often be refilled. The other main type of card involves a card with a special PIN printed on it that allows one to charge calls to a land-line telephone account.