The symbol comprises the following elements:

• Square macromodules that have either a black or white frame

• Quiet zone border

The macromodules are arranged in a square checkerboard pattern that has an odd number of rows and columns. The black-framed and white-framed macromodules alternate throughout the symbol, forming a grid that acts as a finder pattern. The four corners are black-framed macromodules.

If there is not enough data to fill all the macromodules, pad codewords are added.

Each macromodule is a 6 x 6 module unit and encodes a layer ID number and two seven-bit codewords. The one-module frame does not carry data.

This symbology supports the following characters:

• All numeric digits (0-9)

• All seven-bit ASCII characters

• Binary data

• The Guojia Biaozhun (GB) 2312 Chinese character set

Grid Matrix uses the Reed-Solomon algorithm for error correction.

Five selectable levels of error correction are available, which enable a barcode that has had up to 50 percent of its codewords damaged to still be read properly. With maximum error correction levels, Grid Matrix can encode the following numbers of data types:

• Chinese characters: 3 to 391

• Bytes: 5 to 634

• Latin characters: 10 to 1,018

• Numerals: 12 to 1,524

By choosing a lower error correction level, the number of characters that can be encoded increases approximately 80 percent for each data type.

Grid Matrix symbols can be 3 x 3 to 27 x 27 macromodules in size. A minimum quiet zone of six modules is required on all sides.