Micro QR Code
Micro QR Code is a very small QR Code that fits applications that require a smaller space and use smaller amounts of data, such as ID of printed circuit boards and electronics parts, etc. The efficiency of data encoding has been increased with the use of only one position detection pattern.
Micro QR-Code has 4 different symbol sizes (M1-M4). The smallest version (=size) M1 is restricted to numeric data and error detection, M2 may contain also alphanumeric values, and M3 and M4 may use the whole range of the QR-Code character sets.
Valid characters: Alphanumeric and/or bytes