CPC Binary Barcode - Symbology Description

Symbology Description

The applied barcode uses printed and non-printed bars spaced 3 mm apart, and consists of two fields. The rightmost field, which is 27 bars in width, encodes the destination postal code. The leftmost field is 9 bars in width and applied right below the printed destination address. It is currently unclear what this field is used for.

In the postal code field, the rightmost bar is always printed, to allow the sortation equipment to properly lock onto the barcode and scan it. The leftmost bar, a parity field, is printed only when necessary to give the postal code field an odd number of printed bars. The remaining 25 bars represent the actual destination postal code. To eliminate any possibility of ambiguity during the scanning process, run-length restrictions are used within the postal code field. No more than five consecutive non-printed bars, or spaces, are permitted, and no more than six consecutive printed bars are allowed.

The actual representation of the postal code is split into four subfields of the barcode, each with their own separate encoding table. The first and last subfields, which share a common encoding table, are always eight bars in width, and encode the first two characters and the last two characters of the postal code respectively. The second subfield, which encodes the third character of the postal code, is always five bars in width, and the third subfield, which encodes the fourth character, is always four bars wide.