The codes are designed to hold a relatively large amount of data in a small space — just under three kilobytes of binary data, or more than 4,000 letters and numbers.

The 2D versions of barcodes look like squares or rectangles containing many small, individual dots – QR codes are one version – and can hold a lot more information, which is encoded on both ...

A 2D barcode appears as a small, square matrix (like the QR code, for example) instead of vertical lines, and requires an optical scanner or camera (like the one in your smartphone) to access ...