A Data Matrix is a two-dimensional code consisting of black and white "dots" or dots arranged in either a square or rectangular pattern, also known as a matrix. The information to be encoded can be text or numeric data. Usual data size is from a few bytes up to 1556 bytes. The length of the encoded data depends on the number of cells in the matrix. Error correction codes are often used to increase reliability: even if 15 or more cells are damaged or unreadable, the message can still be read. A Data Matrix symbol can store up to 2,335 alphanumeric letters.