How do QR Codes work?
QR codes are an exciting new marketing tool
. Besides containing a URL, a QR code can contain a phone number, an SMS message, V-card data or even plain alphanumeric text. Because of FNC1 Application Identifiers in the encoded data, the scanning device (like a mobile phone) will automatically open the correct application for whatever the QR code contains.
To guarantee that QR codes are the same worldwide, the technical specifications are contained in an ISO standard (ISO-18004). There are forty versions of a QR code
, each differing by the number of data modules (dots) required to store the data. The smallest (Version 1) is a 21x21 array of data elements containing 25 characters; the array increases in size by four modules for each additional version. Version 40, the largest QR code, is 177x177 modules and holds up to 4296 characters of alphanumeric data.
QR codes contain internal orientation calibration and self-alignment markers
. This means whether the QR code is right side up, upside down or rotated 90 degrees or is wrapped around a curved surface, it can still be read.
Even though QR codes contain error correction data, technical limitations in the resolution in most of today’s mobile phone cameras mean the size of a QR code is important – a Version 5 (37x37) or greater QR code runs the risk of incorrect decoding. So if you intend to have your QR code read by mobile phones and PDAs, it is best to stay with Version 4 or lower and a QR code symbol of at least 0.85 inches across.