ACS is an automated COA process offered by the United States Postal Service. Forwarding information is captured in the computerized forwarding system and sent to participating mailers. The seven-alpha-character ACS Participant Code must be obtained from the Address Change Service Department at the National Address Information Center.

You may also use an optional ACS keyline to match ACS data returned by the USPS to records in your list. Keyline data should be entered into an ACS Keyline field in the list layout. The data must be 4 to 16 characters in length. Data entered into the ACS Keyline field must be unique so that specific records can be identified, but must be consistent in regard to length (4 to 16 characters) and type of data (alpha, numeric, or alphanumeric).

Provided the data in the ACS Keyline field contains 4 to 16 characters and meets the requirements, Mail Manager 2010 automatically formats the label by adding the # symbol to the beginning and end of the keyline, and adding spaces and a check digit (if selected). Spaces and # symbols do not count toward the 16-character limit.

For more information regarding the Address Change Service, refer to Publication 8, available from the United States Postal Service.