Marking Requirement: GS1 DataMatrix or Marking Code. What It Looks Like and How It Works, What to Pay Attention To?

Регина Леоненко

DataMatrix is a two-dimensional code used for product marking. The code contains necessary information about the product: product weight, GTIN number, expiration date, manufacturer, etc. The marking code (GS1 DataMatrix) is identical to the marking code used in the Russian Federation.

The marking code includes three main groups of data and may contain one additional group (depending on the product category):

product code, also known as barcode, GTIN, EAN-8, or EAN-13 - a numeric number assigned to each type of product by the International Association GS1, widely used in retail;
serial number, assigned by the digital marking operator and identifies each individual product unit (a pack of cigarettes, a bottle of vodka, a medicine package, etc.);
check key (additional group), a 4-character identifier generated by the operator (applicable to certain product categories);
check code, generated by the operator as a cryptographic protection means of the marking code and allows verification that the code was registered in the marking system;

From the information in this article, you will learn:

What the marking code looks like
Advantages of the marking code
How QR code differs from marking code
Difference between Data Matrix marking code and GS1 Data Matrix
Common errors in forming the marking code

What the marking code looks like

The code is a group of black and white squares combined according to certain rules.

The marking code consists of:

ASCII 232 (FNC1) — a special character that serves as the main feature of the GS1 code. Without this character, technical means will not recognize the code correctly and will not be able to process it properly;
Product code, also known as barcode, GTIN, EAN-8, or EAN-13 - a numeric number assigned to each type of product by the International Association GS1. The number of characters in this code depends on the product category;
Serial number — a unique identification number;
Data group separator ASCII 29 (GS) — separates product information, code, serial number, etc.;
Check key - a 4-character identifier that may contain digits, lowercase and uppercase Latin letters, as well as special symbols (applicable to certain product categories);
Check code, also known as crypto tail — formed by the system and included in the check code composition.

The composition of the marking code directly depends on the product category to which the marked product belongs, so the number of characters in each marking code will vary.

Special GS1 characters are used to identify separate code blocks between variable-length fields. They also serve as separators.

Advantages of the marking code

Unlike linear codes, two-dimensional codes provide a larger amount of data. The marking code contains complete information about the product. Moreover, two-dimensional codes can be read in two planes — horizontally and vertically. Linear codes can only be read in one direction.

Other advantages of the marking code include:

Capacity of up to 3,000 characters;
Area smaller than a QR code by 30-60%;
Different formats (square, rectangle) are used for optimal space utilization;
The code can be read regardless of the background or surrounding space;
In case of minor damage to the code, the information can still be read and restored.

How QR code differs from marking code

At first glance, the marking code and QR code are hard to distinguish. Visually, they look the same, consisting of light and dark small squares. However, there is one difference that helps distinguish the two codes. The marking code contains a finder pattern in the shape of the Latin letter "L". It is located on the left side of the barcode. In the QR code, the finder pattern is made in the form of 3 squares located at the corners.

Main parameters of the marking code:

Allows encoding up to 3 kilobytes of information (capacity depends on the characters used);
Can encode digits, Latin letters, and some selected symbols;
Minimum size of the square code – 10x10 modules;
Maximum size – 144x144;
Step increment – 2 modules in each direction (for QR code, the step is 4 modules).

Difference between Data Matrix marking code and GS1 Data Matrix

Both codes look identical and cannot be distinguished with the naked eye. Professional barcode scanners recognize the marking code instead of GS1 Data Matrix. The difference lies in the attribute or "application identifier".

Main differences:

The marking code standard lacks the concept of "application identifiers", which are present in GS1 Data Matrix;
GS1 Data Matrix contains the control character FNC1.

This control character transforms Data Matrix into a GS1 standard modification. It cannot be added to the string like GS. A special program does this. Accordingly, for the marking code to be generated correctly, the product data must be filled in correctly.

Common errors in forming GS1 Data Matrix

FNC1 (1 special character) not inserted at the beginning;
Text "FNC1" (4 characters) inserted instead of the FNC1 special character at the beginning;
GS inserted instead of the FNC1 special character at the beginning;
Data group separators GS not inserted after variable-length fields (e.g., after the serial number);
Data group separators inserted where they should not be (e.g., after the (01) GTIN field, which has a fixed length and does not require a separator at the end);
Text "GS" inserted instead of the GS special character;
Use of software or algorithms for printing that irreversibly distort the information (e.g., removing characters from the code that they consider unnecessary — arithmetic symbols, brackets, etc.).