These are primarily used by blind-deaf users to access the Internet. A Braille display uses nylon or metal pins to display information. These pins are controlled by software that moves them upwards through a grid so that they form the cells that are used for Braille writing. Braille displays can only display two to four lines of text at a time due to the size of the text. The page can then be automatically refreshed or can be refreshed using a keyboard command, so that the few lines down are displayed.
Braille displays can be used alone or together with a screen reader. There are several screen readers that support Braille displays, the screen reader page has more details about which screen readers support Braille displays.