High Quality Content by WIKIPEDIA articles! The Intelligent Mail Barcode (IM barcode) is a 65-bar code for use on mail in the United States. The term “Intelligent Mail” refers to services offered by the United States Postal Service for domestic mail delivery. IM Barcode is intended to provide greater information and functionality than its predecessors POSTNET and PLANET. Intelligent Mail barcode has also been referred to as One Code Solution and 4-State Customer Barcode abbreviated 4CB, 4-CB or USPS4CB. The complete specification can be found in USPS Document USPS-B-3200E. It effectively incorporates the routing ZIP code and tracking information included in previously used postal barcode standards.