PostBar

PostBar, also known as CPC 4-State, is the black-ink barcode system used by Canada Post in its automated mail sorting and delivery operations.

This particular bar code system is used on "flats" (which are larger-than-letter-size pieces of mail, such as magazines) and parcels.

Z characters are used for address locators, product types, and customer and service information.

B characters are one bar each, and are used to encode base-4 machine IDs for Canada Post's internal uses.

Each barcode begins and ends with an identical pair of bars, known as "start" and "stop" fields.

Placeholders used to detail each PostBar format below are A, N, Z and B for the character sets described above, * for the start and stop fields, # for a space character (two full-height bars followed by one tracker), and [RS-nn] for the error-correction field, where nn is the number of bars used.

52 bar long 4-state barcodes are used by Canada Post for business reply mail (BRM) addressing and payment.

[2] An extended 73 bar long BRM barcode 'C73' , scheduled for availability from 2011, was indefinitely postponed.