Different barcode types: Why?

By John Nachtrieb, Barcode-test LLC. Barcode quality trainer, consultant and testing service provider

It all started in 1974 in an Ohio grocery store, scanning the first UPC symbol. Today there are dozens of different types of barcode symbols. Why is that? Why not just use the humble, reliable UPC everywhere? The reason is evolutionary. New problems create new solutions.

All barcode types do the same thing: they hold and remember data. Barcodes are portable—they travel on paper, plastic, cardboard, wood—just about any surface. The data is secure–it cannot be changed. They are disposable and inexpensive, and they are virtually error-free. Impressive credentials.

CODE 39

The first evolution from the UPC was Code 39. UPC only encodes single digits, 0 through 9, and only 12 of them (well, technically 13).

There was a need to encode alphabetical characters. Code 39 solved that need (thank you David Allais). It encodes 42 different character types:

• 26 upper case alphabetical characters
• 10 numerical characters
• 6 special characters $ . – % / +

Code 39 provided alphanumeric encoding but it had limitations. Upper case letters only was one. Each encoded character took up a lot of space. The barcode could get very long. Like UPC, Code 39 was a present day solution and a problem for future applications.

CODE 128

Code 128 took up the challenge:

• upper and lower case letters
• 10 numerical characters
• all of the ASCII special characters ! @ # $ % ^ & * ( ) _ – + = ~ ,.< > : ; “ { } [ ] | \

Code 128 efficiently packages data in a compact format where two characters can be encoded in the space of one character.

These smaller, high capacity barcodes solved a lot of problems, but were sensitive to slight printing inaccuracies. Still, there was a need for a barcode that could withstand the challenges of printing on the wavy surface of corrugate.

ITF CODE

That problem led to the ITF barcode. ITF stands for Interleaved Two of Five. It also encodes pairs of characters, so it is efficient. But it accommodates large inaccuracies in bar and space widths—perfect for corrugated shipping cartons.

QR CODE

All the while, manufacturing was realizing that barcodes could be useful in their supply chain and assembly operations. The problem was that many of their parts and subassemblies were so small there was no space for a 2” or 3” long UPC, Code 39 or Code 128. Many of the parts were not flat. To solve these problems, Toyota invented the QR Code:

• data capacity of over 7,000 numeric or nearly 4,300 alphanumeric characters
• small footprint for space-limited or non-flat objects
• high tolerance to print inaccuracy
• fast scanning (QR means “quick response”)

DATA MATRIX CODE

As flexible as QR Code is, there were still problems. It was limited to a range of sizes, and required high contrast between the symbol and its background. There was a need to mark very small items such as surgical implants, and to mark directly onto metal or plastic without a label. The Data Matrix Code solves these problems. It can be scaled down to nearly microscopic size or scaled up to sizes measured in acres.

Barcodes continue to evolve and solve new problems, which is why barcodes continue to be important today, and will most likely continue to be useful into the future. What is next?

Visit the Barcode-Test website for additional information.