The Computerized Delivery Sequence (CDS) File is a 5-digit ZIP™ Code based electronic customer product that provides and updates delivery sequence address information by carrier route for qualified mailers. Mailers must initially qualify for CDS information through Address Sequence Service, described in DMM 507.8.

The CDS product is distributed to qualified customers on a weekly or bi-monthly schedule beginning in February.

To obtain additional information about CDS, contact the National Customer Support Center at 1-800-238-3150 or visit the RIBBS™ website at ribbs.usps.gov. Information on qualifying for CDS electronically can also be found on the RIBBS website at ribbs.usps.gov.