Data Matrix
Datamatrix is a 2D symbology standard to encode information in a visual way. The information to be encoded can be text or raw data, usual data size is from a few bytes up to 1 or 2 Kilobytes or characters. The length of the encoded data depends on the symbol dimension is used. Error protection codes are added to increase symbol strength, so even if they are partially damaged, the could still be readed.
Datamatrix symbols are square and made of little modules, that is little squares that represent bits. Depending on the situation a white module is a 0 and a black module is a 1, or vice versa. Every datamatrix is composed of at least two finder patterns or handles and two syncs. Handles are two perdicular lines, coloured the same way as 1 modules, while syncs are like handles with the difference that they are made of alternating black and white modules. Handles are used to achieve a good alignment with the symbol, while syncs are used to sample modules correctly. If the matrix dimension grows, more syncs and handles are added up to 8 both horizontally and vertically. Symbol sizes vary from 8x8 to 144x144.