A few years ago I noticed a little block of dots at the bottom of my insurance bill and wondered what it was. Now you see these blocks on business cards, products, coupons, paperwork and all sorts of places.
These blocks are two dimensional bar codes. The one at the top left is a data matrix code, first developed in 1989. These codes can hold 2,335 characters of data.
The code on the right is a QR, or Quick Response, code developed in Japan in the 1990s by a company called Denso. The QR code holds up to 4,296 characters, and I see it a lot more than the older matrix code. QR codes are oriented with two smaller blocks at the top corners, and one on the bottom left.
Although QR codes have been around for several years, their use exploded for two reasons. The first is that Denso made the QR open source, so anyone could use them. This helped make the QR code more popular than the data matrix and other competing codes.
The second reason for their growth is the widespread use of cellular telephones with cameras. First you need a QR reader application on your phone. If you focus your phone's camera on a QR code, the reader will interpret the code and send you to an Internet link that may contain information about that particular business, coupons or other data.
QR codes can do everything from display simple information and open a web page, to initiating a text message or email. They can even be configured to download a video like a movie trailer, or audio for music.
So next time you're out shopping, look around and I bet you'll spot a lot of these codes.