4 State Barcode


4 State Barcode

Origin and Symbology Term

The British post “Royal Mail” developed the „Royal Mail 4 State Customer Code“ (RM4SCC) in the years 1992 to 1994.

The „Singapore Post“ also specified a „4-State-Barcode“ in 1997, followed by the „Australia Post“ and the „Canada Post Corporation“ in 1998. The PTT Post Netherlands developed the KIX (the Dutch abbreviation for Customer Index) on the basis of the Royal Mail Code in 1998.

The code is called 4 State Code because it uses four bars of different height for the character representation.

Symbol Examples

Australia Post 4-state 37-CUST

Australia Post 4-state 52-FF-MET

Australia Post 4-state 67-FF-MET (HP-Mode)

Australia Post 4-state FCC-45

Royal Mail 4 State Customer Code

Singapore Post 4-state Postal Code

Specific Features of the 4 State Barcode - Variants

Although all 4 State Bar Codes are based upon the same character set and all barcodes look very similar, there are nevertheless strong distinctions, ensuring the uniqueness of the individual codes. For the main part, these distinctions lie in the algorithms for the check digit calculation, but also in the prefix and affix of the information characters. Furthermore, some of these codes only support figures, others however support also letters. Different compression procedures are also used for a compact display of the information characters. The user must in no way carry out any substitutions, as for example to print out the Canadian post barcode (Canadian Post Corporation) for mail to England (Royal Mail Customer Code).

Ranges of Application & Businesses/Trades

  • Post


  • 4 State Barcode
  • One-Width Code

Codeable Character Set

  • 0 1 2 3 4 5 6 7 8 9
  • A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Symbol Layout

  • Each character consists of 4 bars of which 2 have an ascender and 2 have a descender. The track element is present in all bars. The following image shows the four different bars that can appear in the single characters.

    4 state

Check Digits & Data Security

Owing to the predefined setup of every single character, i.e. each consisting of two descenders and two ascenders, the necessary security is already given. Further, the code contains a check digit that is automatically generated by the „Visual Bar Code Designer“. The check digit is calculated separately for the single postal administrations (e.g. Royal Mail, Australia Post, etc.) according to different specifications, so that no mix-up of the 4 State symbols can occur between the individual postal administrations.

Symbol Description

Starting from the left, a symbol consists of:

  • a leading quiet zone
  • a start bit
  • the information characters
  • a check digit
  • a stop bit
  • a closing quiet zone