Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A Data Matrix code is a two-dimensional matrix barcode consisting of black and white "cells" or modules arranged in either a square or rectangular pattern. The information to be encoded can be text or raw data. Usual data size is from a few bytes up to 1556 bytes. The length of the encoded data depends on the symbol dimension used. Error correction codes are added to increase symbol strength: even if they are damaged, they can still be read. A Data Matrix symbol can store up to 2,335 alphanumeric characters.