How does a barcode work?

A barcode essentially is a way to encode information in a visual pattern that a machine can read. The combination of black and white bars (elements) represents different text characters which follows a set algorithm for that barcode type. If you change the sequence of elements you get different text. A barcode scanner reads this pattern of black and white that is then turned into a line of text your computer can understand.

What is a 1D (linear) barcode? What is a 2D barcode?
What is the difference between direct thermal (DT) and thermal transfer (TT)?
How many labels are on a roll?
How does a barcode scanner work?
Do I need any special software to use a scanner?
What factors should I consider when buying an ID Card Printer?
Do I need a single or dual side printer?
Are there any standards for RFID?
What's the difference between passive and active tags?
What's the difference between read-only and read-write RFID tags?
what is a barcode symbology and its type?