# Accessibility

Some users may need specific support because of e.g. some visual impairment. USB braille displays are detected automatically, but most other Most accessibility features have to be enabled manually. On machines that support it, the boot menu emits a beep when it is ready to receive keystrokes. Some boot parameters can then be appended to enable accessibility features. Note that on most architectures the boot loader interprets your keyboard as a QWERTY keyboard.

## USB Braille Displays

USB braille displays should be automatically detected. A textual version of the installer will then be automatically selected, and support for the braille display will be automatically installed on the target system. You can thus just press &enterkey; at the boot menu. Once `brltty` is started, you can choose a braille table by entering the preference menu. Documentation on key bindings for braille devices is available on the `brltty` website.

## Serial Braille Displays

Serial braille displays cannot safely be automatically detected (since that may damage some of them). You thus need to append the `brltty=`driver`,`port`,`table`` boot parameter to tell `brltty` which driver it should use. `driver` should be replaced by the two-letter driver code for your terminal (see the driver code list). `port` should be replaced by the name of the serial port the display is connected to, `ttyS0` is the default. `table` is the name of the braille table to be used (see the table code list); the English table is the default. Note that the table can be changed later by entering the preference menu. Documentation on key bindings for braille devices is available on the `brltty` website.

## Hardware Speech Synthesis

Support for hardware speech synthesis devices is available only alongside support for graphical installer. You thus need to select the Graphical install entry in the boot menu.

Hardware speech synthesis devices cannot be automatically detected. You thus need to append the `speakup.synth=`driver`` boot parameter to tell `speakup` which driver it should use. `driver` should be replaced by the driver code for your device (see driver code list). The textual version of the installer will then be automatically selected, and support for the speech synthesis device will be automatically installed on the target system.

## Board Devices

Some accessibility devices are actual boards that are plugged inside the machine and that read text directly from the video memory. To get them to work framebuffer support must be disabled by using the `vga=normal` `nomodeset` boot parameter. This will however reduce the number of available languages.

If desired a textual version of the bootloader can be activated before adding the boot parameter by typing `h` &enterkey;.

## High-Contrast Theme

For users with low vision, the installer can use a high-contrast theme that makes it more readable. To enable it, append the `theme=dark` boot parameter.