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Barcode encyclopedia : Symbology pdf417

PDF417 | MicroPDF417 | MacroPDF417 | PDF417 truncated

Introduction

PDF417 (Portable Data File) - Multirow, variable length symbology, high data capacity, error correction included.
Stacked symbology, can be read with linear scanners, laser or two dimensional scanners.

Capacity


Large files can be encoded into a series of PDF417 symbols, this symbology name is Macro PDF417.

Major features of PDF417:


Symbol structure :

A typical PDF417 symbol contain 3 to 90 rows, each row consists from lrft to right :
Each symbol character can contain 0 - 928 values which is called "codewords".

Symbol character encodation:
Row encoding : Each row uses character patterns from single cluster : in sequence 0,3,6,0,3,6,0,3,6 ....
ClusterNumber=((RowNumber-1) mod 3)*3

Compaction mode:


Global Label Identifier (GLI)

GLI 0 - correspondends to ISO 8859-1 character set.It is possible to encode data to other languages.

PDF417 Error Correction Levels

PDF417 uses Reed Solomon error correction instead of check digits. This error correction allows the symbol to endure some damage without causing loss of data. Recommended a minimum error correction is level 2. The error correction level depends on the amount of data that needs to be encoded, the size and the amount of symbol damage that could occur. See table below for recommened error correction level depened on the amout of the encoded data.
Error correction levelNumber of ECW
02
14
28
316
432
564
6128
7256
8512
Recommended Error Correction Level
Number of Data Codewords Minimum Error Correction Level
1 -40 2
41 - 160 3
161 - 3204
321 - 8635






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