2.2. Characteristics

MSI is a continuous symbology that is not self-checking, based on Pulse-Width Modulation

2.2.1. Character set

The MSI character set consist of the numbers 0..9 as well as two "guard" characters (representing the beginning and end of the barcode).

So, like Interleaved 2-of-5 and UPC, MSI is an all-numeric language, not support alphabetic characters.

2.2.2. Coding Rule

The bit representation is same with Plessey:

  • Wide bar following by narrow space is a "1" bit.
  • Narrow bar followed by wide space is a "0" bit.

But the digit representation is more simple:

Each digit number is represented by four bit.

Except the start and stop bits, If you only calculate the bar (horizontal black line), the wide bar means ‘1’ and the narrow bar means ‘0’,

then it is the same rule as using binary to represent the digit:

Digit 0 = 0000b

Digit 1 = 0001b

Digit 2 = 0010b

Digit 3 = 0011b