The five IMb fields are the Barcode Identifier, the STID, the MID, the Serial Number, and the Routing Code (ZIP Code). Each field has its own unique set of standards, explained below:
The Barcode Identifier field should be “00” (zero-zero) with one exception: automation-price eligible flat mail bearing a printed optional endorsement line (OEL). When mailers prepare flat-size pieces using IMb tracking codes to meet automation-price eligibility requirements, the IMb tracking codes on any pieces bearing printed OELs must contain the Barcode Identifier corresponding to the printed OEL used. See the Barcode ID Reference Table on PostalPro to determine the correct Barcode IDentifier.
The attributes that determine which STID should appear in an IMb tracking code are the class of mail, the ACS service selected, and whether IV-MTR service is desired. See the Service Type IDentifier for Ballot Mail fact sheet included in this kit or visit PostalPro at https://postalpro.usps.com/mailing/service-type-identifiers for more information about STIDS.
The MID is explained in Step 2, above. IMbs must contain a valid MID.
The Serial Number, in conjunction with the MID and class of mail, can uniquely identify the mailpiece. Although Serial Number uniqueness is not required to qualify for basic automation prices, barcoding mailpieces with unique serial numbers enables visibility of individual pieces. If an individual mailpiece or ballot mailpiece does not have a unique identifier, it cannot be tracked through IMb. The Postal Service strongly recommends utilizing Full-Service Intelligent Mail instead of Basic Intelligent Mail. Full-Service Intelligent Mail requires that mailpieces be uniquely identified, and the tracking code cannot be reused for a period of 45 days.
The Routing Code can contain a 5-digit ZIP Code, 9-digit ZIP+4® code, or 11-digit delivery-point code. To obtain automation discounts, a Delivery-Point ZIP Code from CASS™-certified (Coding Accuracy Support System) software is required. Mailers may opt not to populate the ZIP Code and use the IMb tracking code only for tracking the mailpiece. If populated, it must never be padded with leading or trailing zeros that are not part of a valid 5-, 9-, or 11-digit ZIP Code. The IMb concatenates the five fields in this way:
Although Serial Number uniqueness is not required to qualify for basic automation prices, barcoding mailpieces with unique serial numbers enables visibility of individual pieces. If an individual mailpiece or ballot mailpiece does not have a unique identifier, it cannot be tracked through IMb. The Postal Service strongly recommends utilizing Full-Service Intelligent Mail instead of Basic Intelligent Mail. Full-Service Intelligent Mail requires that mailpieces be uniquely identified, and the tracking code cannot be reused for a period of 45 days.
