Credit Card Preamble

A credit card preamble—sometimes called a credit card prefix, issuer identification number (IIN), or bank identification number (BIN)—is a digit or series of digits at the beginning of a credit card number that identifies the type of card or company that issued the card.

Adhere to the following rules for governing a valid credit card preamble:

• The Start and End preambles must end with an asterisk (*) (for example, 304*).

• The number of digits in the Start and End fields must be the same.

• The number of digits in the Start and End fields cannot exceed the Length defined.

• The value of the End field must be greater than the value of the Start field.