5.2. Accessibility
| Chapter 5. Booting the Installation System |

## 5.2. Accessibility

Some users may need specific support because of e.g. some visual impairment. USB braille displays are detected automatically (not serial displays connected via a serial-to-USB converter), but most other 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 (see also Section 5.1.5, “The Boot Screen”). Note that on most architectures the boot loader interprets your keyboard as a QWERTY keyboard.

### 5.2.1. Installer front-end

The Ubuntu installer supports several front-ends for asking questions, with varying convenience for accessibility: notably, `text` uses plain text while `newt` uses text-based dialog boxes. The choice can be made at the boot prompt, see the documentation for `DEBIAN_FRONTEND` in Section 5.3.2, “Ubuntu Installer Parameters”.

### 5.2.2. 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 Enter 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.

### 5.2.3. 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`` boot parameter to tell `brltty` which driver and port it should use. `driver` should be replaced by the two-letter driver code for your terminal (see the BRLTTY manual). `port` should be replaced by the name of the serial port the display is connected to, `ttyS0` is the default, `ttyUSB0` can be typically used when using a serial-to-USB converter. A third parameter can be provided, to choose the name of the braille table to be used (see the BRLTTY manual); the English table is the default. Note that the table can be changed later by entering the preference menu. A fourth parameter can be provided to pass parameters to the braille driver, such as `protocol=foo` which is needed for some rare models. Documentation on key bindings for braille devices is available on the `brltty` website.

### 5.2.4. Software Speech Synthesis

Support for software speech synthesis is available on all installer images which have the graphical installer, i.e. all netinst, CD and DVD images, and the netboot gtk variant. It can be activated by selecting it in the boot menu by typing `s` Enter. The textual version of the installer will then be automatically selected, and support for software speech synthesis will be automatically installed on the target system.

The first question (language) is spoken in english, and the remainder of installation is spoken in the selected language (if available in `espeak`).

The default speech rate is quite slow. To make it faster, press CapsLock+6. To make it slower, press CapsLock+5. The default volume should be medium. To make it louder, press CapsLock+2. To make it quieter, press CapsLock+1. To get more details on the browsing shortcuts, see the Speakup guide.

### 5.2.5. Hardware Speech Synthesis

Support for hardware speech synthesis devices is available on all installer images which have the graphical installer, i.e. all netinst, CD and DVD images, and the netboot gtk variant. You thus need to select a “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.

### 5.2.6. 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` `fb=false` 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` Enter.

### 5.2.7. High-Contrast Theme

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

### 5.2.8. Zoom

For users with low vision, the graphical installer has a very basic zoom support: the Control++ and Control+- shortcuts increase and decrease the font size.

### 5.2.9. Preseeding

Alternatively, Ubuntu can be installed completely automatically by using preseeding. This is documented in Appendix B, Automating the installation using preseeding.

### 5.2.10. Accessibility of the installed system

Documentation on accessibility of the installed system is available on the Debian Accessibility wiki page.

5.1. Booting the Installer on 32-bit PC |  | 5.3. Boot Parameters