The Royal Mail 4-state is a barcode symbology for use in automated mail sort process. 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, of which two are ascenders and two descenders. The tracking region is present in all bars.
Ascending Region;
Tracking Region;
Descending Region.
A Royal Mail 4-state Barcode. "1234567890123" is a number encoded in the barcode.