A computer tells you how much time or how many units you have left on your card, and how to use other features your card may offer. Typically, each unit equals one domestic minute. If your pre-paid phone card can't be recharged, that is, if you can't buy additional minutes by phone for the card, you'll need to buy another card once you've used up the time or minutes. Resellers buy telephone minutes from carriers. Issuers set the rates and provide toll-free customer service and access numbers.
Distributors get the cards to retailers.
Retailers sell the cards. When you buy a pre-paid phone card from a store, it's important to remember that you've bought a telephone service, not a product. The store doesn't control the quality of the service. To make sure you're getting what you've paid for, you may want to buy a small denomination first to test out the service, and check with friends or relatives to find out their experience with the card. As the pre-paid phone card industry mushrooms, and as more people buy and use the cards, some problems are coming to light.