PDF417

What is the PDF417?

The PDF417 is a stacked linear barcode. It is usually classified as a two dimensional (2D) barcode like the QR code or the datamatrix code.

The PDF417 was invented by Ynjiun P. Wang in the early nineties. The term ‘PDF’ stands for ‘portable data file’ (not to be confused with Adobe’s PDF file, which stands for ‘portable document format’). The numbers 417, on their turn, represent the code’s pattern: 4 bars and spaces and a 17-part codeword.

The ISO/IEC 15438:2015 standard specifies the PDF417 barcode.

Capacity

The PDF417 barcode can encode several types of data, including text, numbers, files or even signatures. It can hold up to 2.000 characters or 1108 bytes.

Elements of the PDF417

The PDF417 is made of 3 to 90 rows. Each row has the following elements:

• A quiet zone (a minimum amount of white space before the start pattern).
• A start pattern (used to identify the format of the barcode).
• A left row codeword (used to encode information about the row).
• 1 to 30 codewords (used to represent text, numbers or other symbols).
• A right row codeword (used to encode more information about the row).
• A stop pattern.
• A second quiet zone (another minimum amount of white space after the stop pattern).

Types of PDF417 barcodes

The PDF417 barcode has three different formats:

• The Macro PDF417, used to store more information than the standard version of the PDF417.
• The Micro PDF417, a variant that can only encode up to 150 characters. It is rarely used.
• The Compact (or Truncated) PDF417, a size-reduced variant of the standard version.

Where is the PDF417 barcode used?

Although their capacity is limited compared to modern barcodes, PDF417 barcodes are still used in a variety of cases, including:

• Transportation (e.g. airline boarding passes).
• Postal services.
• ID documents (e.g. Visas, driver’s licences).
• Inventory management.

PDF417 vs QR and datamatrix codes

PDF417 barcodes have several limitations. This explains why QR codes and datamatrix codes are often preferred.

In particular, QR and datamatrix codes offer the following advantages compared to PDF417 barcodes:

• They are smaller, which makes them an ideal solution for small items.
• They can store more information.
• They can be scanned faster.
• They offer more customization.