Type
Content
Phones that scan it can join the network without typing the password.
Scanning it offers to call this number.
Look
Image size
About 1200 pixels wide. Use Print for signs and posters, or SVG for any size.
Margin around the code
Error correction
Higher still scans when the code is scratched or partly covered, but makes it denser.
Bar height
Colors
Low contrast: some scanners may not read this. Dark code on a light background works best.