Abstract: An optically readable matrix (100) has four intersecting sides of approximately equal length defining a perimeter and includes a binary code formed from light and dark squares of substantially equal sizes located within the perimeter. The matrix (100) comprises first and second orientation squares (105, 110) included in the light and dark squares and located in opposite corners of the matrix (100). Each of the orientation squares (105, 110) preferably includes a contrasting circular area (115, 120) located in a predetermined position within the orientation square (105, 110) and having a predetermined size relationship with the orientation square (105, 110). Such a matrix (100) may be formed on a printed circuit board (505) for use in an electronic device (500) to convey information about the printed circuit board (505). An apparatus (600) for decoding the matrix (100) includes an optical scanner (610) for scanning the matrix (100) and for locating the orientation squares (105, 110).