The Aztec code is a matrix code. It can be recognized by the fact that it has a square search element in the middle surrounded by several lines arranged in a square. The Aztec code uses the ASCII character set with 128 characters and also Extended ASCII with 256 characters. The Aztec code can be used to represent up to 3,750 characters.
The encoded characters surround square patterns the square search element placed in the center. The characters are arranged from the inside to the outside and determine the size of the Aztec code, because each character added surrounds the existing structure on the outside in a ring. The code is equally suitable for encoding characters of small size and characters of large size. The smallest character is the module, which corresponds to a square dot. The module size should be between 15 mm and 30 mm to be detected by most readers.