Image courtesy of Smithsonian's National Postal Museum
The CSBCS – Carrier Sequence Bar Code Sorter has been deconstructed for visitors to the exhibit – the image on the wall is the machine and five pieces of the machine that have been “pulled out” to help show visitors how it operates.

Carrier Sequence Bar Code Sorting was a key element of the postal system beginning in the 1990s. As more information became available through better address reading and recognition software, the CSBCS was created to sort mail not just to a city, or even post office within a city, but to each carrier’s specific mail route. Workers are able to take trays of letters from this machine and forward them directly to a specific letter carrier.