Solid bordersTwo adjacent borders help establish orientation.
Alternating bordersHelp determine the module spacing.
Internal areaPayload and ECC200 error-correction codewords.
A Chestny ZNAK marking in our main scenarios is a GS1 DataMatrix symbol. It is recognised by its square shape, its L-shaped finder pattern and its internal module grid.
At the data level, the string usually contains several logical blocks. The most practical ones are the GTIN, the serial number and a security / verification part.
The GTIN identifies the product type. The serial number identifies the exact individual unit.
The security part may be represented in different ways, such as the 91/92 pair or a shorter 93-based variant depending on the product group and the specific structure.
Those security fields are not the same as ECC200 error correction. ECC200 helps decode a damaged image; the security part belongs to code validation inside the marking ecosystem.
That is why geometry, field structure and product context all matter when a damaged symbol is analysed.