PDF417 Barcode
PDF417 barcode is a multirow, continuous, variable length symbology which has high data capacity. It is a stacked symbology invented in 1991 at Symbol Technologies. PDF stands for Portable Data File, and the symbology consists of 17 modules each containing 4 bars and spaces (thus the number "417").
Every symbol has between three to ninety rows. Every symbol includes at least two error correction codewords and this is selectable up to 512 Error Codewords. The error correction codewords can be used to correct erasures (where a character is undecodable) and actual errors(where the position and value of a character is unknown).
Error Correction
PDF417 barcode uses Reed Solomon error correction. This error correction allows the symbol to withstand some damage without causing loss of data. This high level of error correction is more advanced than linear barcodes with check digits. The Reed Solomon error correction can add significantly to the size of the PDF417 barcode but should not be a problem as the barcode is two-dimensional.