Screen readers - Definition and Overview

A screen reader is a software application that attempts to identify and obtain what is being displayed on the screen. This is then presented to a blind user as speech (by text-to-speech) or by driving a Braille display.

The first screen readers captured text sent to the command line. With the arrival of graphical user interfaces, they employed new low-level techniques to allow them to capture what was being sent to the screen by the operating system. More recently operating systems and applications have made efforts to support screen readers by providing them with alternative and accessible representations of what they are displaying on the screen. Examples include Microsoft Active Accessibility and the Java Access Bridge.

A screen reader can read, among others:

• The operating system in general.
• Text-mode programs, like DOS and telnet sessions.
• Any GUI graphics and text on the screen.
• Web browsers and email and usenet clients.
• Office suite programs.

Leading screen readers include:

• JAWS by Freedom Scientific
• Window-Eyes by GW Micro (http://www.gwmicro.com)
• Hal by Dolphin (http://www.dolphinuk.co.uk)
• OutSpoken by Alva Access Group (discontinued for Mac OS 9)
• Speakup (http://www.linux-speakup.org), a linux screen reader

Windows 2000 and XP come with a very simple built-in screen reader called Narrator. This can be activated by the key combination Windows Key + U. It can be used for Windows Explorer and Notepad but not Office or Internet Explorer.

In 2004, Apple announced that a future version of Mac OS X would include a full-featured screen reader, later named VoiceOver.

External link

• Apple: VoiceOver (http://www.apple.com/macosx/tiger/voiceover.html)