dLSoft  barcode & labelling software     


The Mailmark barcode type is used by the Royal Mail in the UK and by Royal Mail customers using barcode enabled options of the existing Retail and Network Access product portfolios. There are two types of Mailmark available: a 2D version, which includes spare space for customer use, and a 4-state version.

A Complex Mail Data Mark (CMDM) is a 2 dimensional barcode that has the specified format of a Datamatrix type ECC200 code complying with the international standard ISO/IEC 16022, version 2006.

A CMDM Mailmark® barcode can be any of the following formats of Data Matrix type ECC200 as defined in ISO/IEC 16022:

Mailmark type 7 image
Format 7 (24 x 24 modules)

Mailmark type 9 image
Format 9 (32 x 32 modules)

Mailmark type 29 image
Format 29 (16 x 48 modules)

The module size of Mailmark® CMDMs must be in the range of 0.50 – 0.70mm.

The data used to generate the barcode is summarised in the table below.

Field Length example
UPU country ID 4 JGB<space>
Information type ID 1 0
Version ID 1 1
Class 1 1
Supply chain ID 7 0000000
Item ID 8 12345678
Destination postcode 9 AB19XY1A
RTS flag 1 0
RTS postcode 7 7 spaces
reserved 6 6 spaces
Customer content variable  

All dLSoft products that support the Datamatrix barcode may be used for generating CMDM Mailmark symbols.