CASS (Coding Accuracy Support System) certification is the process of matching your mailing address list to the USPS master list of zip+4 codes. Coding Accuracy Support System is used to improve direct mail delivery rates and qualify for postal automation discounts. CASS certification ensures that your custom printed direct mailpieces reach their destination with an absolute minimum of wasted postage and expense. DALLAS PRINTING uses CASS-certified mailing software to ensure that it can perform a correct match even when errors are present in the mailing address; this process also helps fix incorrect addresses. When the mailing is delivered to the post office business mail entry unit, DALLAS PRINTING provides a certification report to the U.S. Postal Service to obtain the postage discounts.