The Royal Mail 4-state barcode is used for automated mail sort process. Encoding is carried out in alphanumeric format (0-9, A-Z). There are 38 valid characters in the entire character set:
Valid symbols: |
numeric characters 0-9; alpha characters A-Z |
Length: |
Variable |
Check digit: |
none |
A barcode consists of four bars and divided into 3 regions, two of them are ascenders and two descenders. The tracking region is present in all bars. The picture below shows the structure of the Royal Mail 4-state barcode:
Ascending Region;
Tracking Region;
Descending Region.
A Royal Mail 4-state Barcode. "1234567890123" is a number encoded in the barcode.