Understanding Postal: Get Smart

What Kind of Barcode?
The IMB is a 65-bar, four-state (e.g., four different types of bars in the code) barcode that contains 31 digits of data. These encode:
* the delivery-point address routing code used by the USPS to sort and track mail;
* any special services requested by the mailer, such as Address Change Service or Confirm;
* the class of mail and mailer’s ID code (a new feature being introduced with IMB); and
* the unique identity of the mail piece.