A delivery point is a single mailbox or other place where mail is delivered. It differs from the street address in that each address can have multiple delivery points, such as an office building. This is a specific set of numbers between 00 and 99, assigned to every address. When combined with the ZIP4, the delivery point provides a unique identifier for every deliverable address served by the USPS.
delivery_point_bar_code adds an additional digit, called the check digit. This digit is used by barcode sorters to check if the ZIP or ZIP4 contain errors. The
delivery_point_bar_code allows for automated mail sorting in the order in which the carrier delivers the mail. Delivery Point Barcodes and ZIP4 code are verified via CASS and DPV certification on a monthly basis to ensure postal discounts.
- Delivery Point - Wikipedia.