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RM4SCC is abbreviation of Royal Mail 4-state Customer Code. It is also known as CBC (Customer Bar Code), RoyalMail4SCC and Royal Mail Barcode. RM4SCC is mainly used in the Royal Mail to speed up sortation procedure in the Cleanmail service. It is a height-modulated barcode symbology with maxmuim 9 characters encoded. RM4SCC is based on the UK Post Code system but also used in Singapore post office for Postal code and automatic mail sorting. RM4SCC provides the detailed information of the address, recipients postal code and receiver. An International Prefix and a Delivery Point Suffix is optional if required.
Data Encoded in RM4SCC
RM4SCC is an alphanumeric symbol which could encode uppercase alphanumeric characters. RM4SCC is a height-modulated symbology with variable length. The 38 valid characters set include:
  • 10 Numeric characters from 0 to 9;
  • 26 Alphanumeric symbol (upper cases) from A to Z;
  • Open and close brackets () or [], please note the close brackets could only used as start bars and stop bars.
Component of RM4SCC
The RM4SCC is consisted of a set of distinct bars and spaces for each character. Each character is made up of four bars, 2 of the bars are ascenders while the others are descenders. All bars have the track element. A complete RM4SCC composed of the parts:
  • A leading start bar; the leading and stop bar helps the RM4SCC could be read at any direction. It is the leftmost character next to the first significant data character.
  • Characters encoded in the message. Each character is consisted of the distinct bars and spaces. 2 characters which refers to the DPS. It is composed of a number and letter.
  • Checksum character;
  • Stop bar; the code density is 20 to 24 bars per 25.4 cm. It is immediately followed the checksum digit.
  • A quiet zone; the quiet zone must be at least 2mm in each direction.
  • Clear zones; Clear zones are remain free of markings. It is used for machines to print barcode reading and address locating.
The RM4SCC symbol is made up of a series of lines that constitute any of four states. The four states are Tracker, Ascender, and Descender; the second states is Tracker and Ascender; the third one is Tracker and Descender and the fourth one Tracker.
Checksum Digit of RM4SCC
Checksum digit is necessary to offer error correction of RM4SCC barcode. Checksum digits make sure the rest of the barcode is correct. RM4SCC employs the modulo 6 to calculation the checksum digit. Follow the steps:
  • Computing the top and bottom half values separately. Find the right most digits assigned it to weight value 0, then in sequence of 1, 2, 3, 4 from right to left.
  • Multiple the upper half values with 1 if the ascender is presented; otherwise multiplier is is 0.
  • Summary all the results in each half. Then add one number which could be even divisible by 6. The number added is the smallest value added that could be even divisible by 6. It is the checksum digit. If the result could be even divisible by 6, “0” is the checksum digit.
Note: The Start and Stop bar is not included in calculation of the checksum digit.
RM4SCC & Cleanmail System
RM4SCC can be used with Royal Mail's clean mail system, it is also known as CBC (Customer Bar Code) in this system. CBC means printing barcode also the address and postcode on the letter. The barcode enables the machine in post office to sort out letter for quick delivery.