PDF417 - Citizendia

PDF417 is a stacked linear bar code symbol used in a variety of applications, primarily transport, identification cards, and inventory management. A bar code (also barcode) is an optical Machine-readable representation of data Transport or transportation is the movement of people and goods from one place to another Inventory is a list for goods and Materials, or those goods and materials themselves held available in stock by a Business. PDF stands for Portable Data File. The PDF417 format was developed by Symbol Technologies, and has spawned an Open Source decoder project[1] together with an Open Source encoder[2]. Symbol Technologies is a manufacturer and worldwide supplier of mobile data capture and delivery equipment

1 Features
2 Format
3 Documentation
4 External links

Features

In addition to features typical of two dimensional bar codes, PDF417's capabilities include:

Linking. A bar code (also barcode) is an optical Machine-readable representation of data PDF417 symbols can link to other symbols which are scanned in sequence allowing even more data to be stored.
User-specified dimensions. The user can decide how wide the narrowest vertical bar (X dimension) is, and how tall the rows are (Y dimension).
Public domain format. Anyone can implement systems using this format without any license. The verb license or grant license means to give permission The noun license is the document demonstrating that permission

Format

The PDF417 bar code (also called a symbol) consists of 3 to 90 rows, each of which is like a small linear bar code. Each row has:

a quiet zone. This is a mandated minimum amount of white space before the bar code begins.
a start pattern which identifies the type of symbol as PDF417. Every type of bar code symbology has a unique start and stop pattern.
a "row left" codeword containing information about the row (such as row number and what error correction rate the row is using)
- 1 - 30 data codewords : Codewords are a group of bars and spaces representing one or more numbers, letters, or other symbols.
- All rows have the same number of codewords.
- Every codeword contains four bars and four spaces (where the 4 in the name comes from).
- The total width of a codeword is 17 times the width of the narrowest allowed vertical bar (the X dimension). This is where the 17 in the name comes from.
- Each codeword starts with a bar and ends with a space.
- There are 929 codewords to choose from, 900 for data, and 29 for special functions.
- Each codeword is printed using one of three distinct clusters:
  - A cluster is a bar-space pattern for each of the 929 codewords
  - no bar-space pattern is repeated between clusters
  - The row number determines which cluster to use
  - the cluster is the same for all codewords in a row.
  - The purpose of clusters is to determine which row (mod 3) the codeword is in, allowing the scan to be skewed from the horizontal. For instance, the scan might start on row 6 at the start of the row, and be on row 10 at the end.
a "row right" codeword with more information about the row.
a stop pattern.
a quiet zone.

Along with Data Matrix, this symbology can be used to generate postage accepted by the United States Postal Service. A Data Matrix code is a two-dimensional matrix Barcode consisting of black and white square modules arranged in either a square or rectangular A postage stamp is an adhesive paper evidence of pre-paying a fee for postal services

Documentation

Official standard

Note that although it is in the public domain, a fee is charged to purchase the standard. The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone

External links

© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
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Contents

Features

Format

Documentation

External links