Credit Card Preamble Rules

Adhere to the following rules that govern 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.