Intelligent Mail Barcode (IMB)

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Posted Aug 17, 2009 10:07:30 AM by DecisionPoint Team & filed under

imb1The Intelligent Mail Barcode (IMB)—also known as OneCode and the 4-State Barcode—is a height-modulated barcode that encodes a 31-digit string of mail data into 65 vertical bars.

In 1980 the Postal Service invented a unique barcoding method called POSTNET, for POSTal Numeric Encoding Technique for encoding ZIP+4 code information. The Intelligent Mail initiative was announced by the USPS in 2003, became available in 2006, and was expanded upon and enhanced in 2007.The Intelligent Mail Barcode replaces the POSTNET and PLANET barcodes. This barcode will be required starting in fall of 2009 for companies looking to receive the maximum USPS automation discounts.

With IMB, businesses can track their mail through the entire mail system, both internally and externally. A database is created by using IMB to create a mail tracking system. Supplemental data can be added to this database and data mining techniques can be implemented. Another major benefit for businesses is enhanced address corrections which should reduce Undeliverable As Addressed (UAA) mail. Electronic Address Change Service (ACS) are free for First Class Mail when companies use the Full-Service Intelligent Mail Barcode.

Use of IMB is currently optional. Originally, the USPS planned to switch over from the POSTNET bar code to IMB in January 2009, but now businesses can continue using POSTNET until May, 2011. However, as of the fall of 2009, mailers will be required to implement the Full-Service Intelligent Mail Barcode to qualify for maximum postal discounts.

At first glance, the new IMB looks similar to POSTNET, but IMB has both ascender and descender bars as well as full bars and half bars. The new code can hold much more data in the same space. The old POSTNET code held only zip code and routing information while the new IMB indicates sorting level, class of mail, optional services requested, the Mailer ID, an optional serial number identifier for the piece, and all the zip and routing information that was in the original POSTNET code.

The USPS assigns Mailer IDs based on mail volume. A 9-digit ID will be assigned to mailers with an annual volume less than 10 million pieces while those mailing more than 10 million pieces will be assigned a 6-digit ID. Both Basic and Full Service IMB are available. The Serial Number/Piece ID field is the primary difference between the Basic and Full IMB. In Basic IMB, a business can pad this field with zeros or assign an internal value. With Full Service IMB, businesses must ensure each Serial Number issued is unique for at least 45 days.

To facilitate adoption of the Intelligent Mail Barcode, the USPS developed and is making available at no charge a number of tools and resources available from the Rapid Information Bulletin Board System (RIBBS) Web site at:


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