USPS uses a system known as CONFIRM to track items through its delivery process, which uses the IMb – Intelligent Mail Barcodes, printed on the packages, that provide a unique code for each one. The IMbs are read by a Intelligent Mail Devices (IMDs) which feed the information into a central database.
The IMbs are read at each hand over along the route, either by fixed or hand held units, which provides an accurate way of determining when each stage is reached. The customer has different levels of access to the tracking data dependent upon the level of service that they purchased. If Priority Mail Express was selected then entering the label number will provide point-by-point tracking information; USPS Tracking, Certified Mail and Registered Mail will show when it was despatched for delivery. IMb technology can also be used to track incoming mail and also identify the sender. In addition, there is the ADVANCE system which provides a series of reports for companies that are sending out bulk mailings of advertising material and periodicals. This can provide useful information on the intended audience, incorrect addresses and confirmation that the service purchased was achieved successfully. This replaces manual publication tracking requests and provides a much higher level of information at a reduced cost.