About PDF417 Barcodes
PDF417 is a stacked, linear 2D barcode symbology developed in 1991 by Symbol Technologies. The "PDF" stands for Portable Data File, indicating its ability to store extensive files of text, numbers, and binary data directly in the barcode without requiring a database connection. Unlike matrix 2D codes (like QR Code), PDF417 consists of multiple consecutive linear barcode rows stacked on top of each other.
How PDF417 Encoding Works
PDF417 consists of 3 to 90 rows of linear barcode segments. Each row features start and stop guard patterns, data characters, and error correction codes. It can store up to 1,850 alphanumeric characters or 2,725 numeric digits in a single barcode. PDF417 features adjustable security levels (0 to 8) using Reed-Solomon error correction, allowing it to recover from physical tearing or printing smudges.
Common Applications and Industries
PDF417 is the official standard for government identification documents, printed on the back of driver's licenses in the US and Canada. It is also used on airline boarding passes, railway tickets, package delivery shipping labels (such as FedEx and USPS package tracking), and customs clearance papers. It allows officers and gates to read complete passenger or cargo details instantly.
Advantages & Limitations
PDF417 acts as a complete offline database, holding large amounts of text, serial structures, and binary data securely. It can be read by older linear laser scanners configured for stacked codes. The limitation of PDF417 is its large physical footprint, as the stacked design makes it much wider and taller than modern matrix codes like Data Matrix.