PDF417, or Portable Data File 417, is a two-dimensional (2D) stacked barcode symbology capable of encoding over a kilobyte of data per label. It was developed by Symbol Technologies (1989-1992) and is currently maintained by ISO/IEC. Large amounts of text and data can be stored securely and inexpensively when using the PDF417 symbology. The printed symbol consists of several linear rows of stacked codewords. Each codeword represents 1 of 929 possible values from one of three different clusters. A different cluster is chosen for each row, repeating after every three rows. The data is encoded using one of three compaction modes: Text compaction mode, Binary compaction mode, and Numeric compaction mode. Barcode Professional products support the following PDF417 Compaction modes: Text: It allows encoding all printable ASCII characters, i.e. values from 32 to 126 inclusive in accordance with ISO/IEC 646, as well as selected control characters such as TAB (horizontal tab ASCII 9), LF (NL line feed, new line ASCII 10) and CR (carriage return ASCII 13). Binary: It allows encoding all 256 possible 8-bit byte values (ISO/IEC 8859-1). This includes all ASCII characters value from 0 to 127 inclusive and provides for international character set support. Numeric: It allows efficient encoding of numeric data strings. Auto: It switches between Text, Binary and Numeric modes in order to minimize the number of codewords to be encoded. PDF417 Error Correction Level PDF417 uses Reed Solomon error correction instead of check digits. This error correction allows the symbol to withstand some damage without causing loss of data. The error correction levels range from 0 to 8. The recommend minimum error correction level is 2.