General Information

M-E-R-L-I-N is an acronym for Mail Evaluation Readability Lookup INstrument. The MERLIN™ process is an automated verification method that will be used to verify letter-size and flat-size mailings against the standards in the DMM™ documentation.

  • Definition
    • The MERLIN process verifies First-Class Mail®, Standard Mail® and Periodical items.
  • Resources
    • Customers can utilize the MERLIN contact list provided by the United States Postal Service® for their questions and concerns. Normally, the USPS® MERLIN contact will be the District Manager of the BMEU. Issues that cannot be resolved at the district level will be elevated to the USPS Area MERLIN Coordinator.
    • MERLIN Information website (
    • Customers can also check their industry trade associations, mail service providers, and vendors to find out what additional MERLIN resources are available.
  • Incorrect Mailing Information
    • MERLIN™ cannot detect when mailing information is entered incorrectly. It may be necessary to revise information entered or to re-run the sample.
      • Example: Operator input the net weight rather than the gross weight on a permit imprint mailing, the piece count determined by MERLIN would be inaccurate. The operator may go back to the entry point and enter correct data.
  • Requirements
    • MERLIN™ is able to verify a wide variety of mailpieces because of a sophisticated feeding mechanism. The MERLIN™ process requires an environmentally controlled location (a loading dock is NOT an acceptable location):
      • An ambient environment, with a temperature and relative humidity control necessary for the accuracy of the scale.
      • Heating /AC vents or fans cannot discharge air directly onto the scale section of the MERLIN™ process.
      • This information is in the site preparation handbook.
    • The MERLIN process requires a minimum of 178 square feet (13.0 x13.7 feet).
    • The United States Postal Service® office is responsible for providing power and data connections at the United States Postal Service facility and Detached Mail Units (DMUs).
  • Tolerance Levels
    • Currently there are two levels of tolerance for barcode readability:
      • Mailings with results between 89% - 80% will be charged an adjustment factor.
      • Mailings with results of 79% and below will be charged non-automation prices for the automation portion of the mailing.
    • Test results are rounded to the nearest whole number.
  • The Separator Card is used to identify individual mailpieces within a sample. They are placed in front of the initial piece of each mailpiece within a sample.

MERLIN® Process

  • Manually entered data
    • The data entered manually by the employee relating to the mailings being tested before verification is entered into a mailing profile such as:
      • Permit Number
      • Type of Permit
      • Name of permit holder
      • Mailing Agent
      • Total pieces in the mailing
      • Total postage for mailing
      • Number and types of containers
    • The employee then follows the MERLIN™ screens to identify the class and type of mailing being run (these are point and click screens). If a mailing is an identical permit imprint mailing, gross weight, tare weight and container information is entered.
    • The balance of screens does not require operator input.
  • Verifications
    • Verifications a

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