Braille displays connect to a computer or phone and work together with a screen reader, showing a line of text (commonly 14 to 80 characters) in braille at a time, refreshed as the user reads along or navigates the page. Some deafblind users rely on a braille display as their only way to access digital content, since speech output is not an option for them.
Braille displays depend entirely on the same underlying accessibility tree and semantic structure a screen reader uses, so there is no separate technical requirement for braille support beyond building a genuinely accessible, well-structured page.