How Does a Calling Card Work?

Carrier Agreements

Although the name of a phone company does not usually appear on calling cards, the prepaid card system is based on relationships between phone carriers and card companies. Card issuers agree to purchase large blocks of calling time from long-distance carriers, and the sides then negotiate how many calling cards to produce and what the base cost or cost per minute for the cards should be.

Programming of Cards

Card issuers then set up the access numbers and PIN numbers for a new set of prepaid cards. Each card is assigned a unique access number, which is usually an 800 phone number, and a PIN number for security purposes. The card company sells its prepaid cards to convenience stores and other retailers with a certain number of minutes programmed into the card.

Using a Calling Card

Customers can use prepaid cards from any phone line. In order to use the card's minutes, the customer first dials the 800 access number listed on the back of the calling card. He is then automatically redirected into the long-distance carrier's network and instructed to enter his PIN number. After clearing this level of security, the customer can enter any area code and phone number. The card's timer will then begin and will count the number of minutes the customer uses. This amount of time will be subtracted from the card's remaining total at the end of the call.