Because we virtually never actually handle or “swipe” the credit cards that are used, the credit card company requires us to enter certain information into the terminal depending on the type of card used. Visa, MasterCard, American Express, Discover and Diner’s Club all require the address your card is BILLED to. In addition, Visa and MasterCard require the v-code, or 3-digit code on the back of your card at the end of the signature line and 4-digit code for Amex. That code verifies that the cardholder has the card in hand and is less likely to be committing fraud. In addition, entering the required information keeps our discount rate (the amount the credit card people charge us for taking credit cards) as low as possible.