Screen reader
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A screen reader is a software application that attempts to identify and interpret 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, word for word, as it was sent to the visual display. With the arrival of graphical user interfaces, screen readers employed new low-level techniques to allow them to capture what was being sent to the screen by the operating system. They also came to communicate information on menus, controls, and other visual constructs to permit blind users to interact with these constructs. 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 (http://java.sun.com/products/accessbridge).
A screen reader can read, among others:
- The operating system in general.
- Text-mode programs, like DOS and telnet sessions.
- Any GUI icons and text on the screen.
- Web browsers.
- 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
- Brltty (http://mielke.cc/brltty), another linux screen reader
- VoiceOver for Mac OS X by Apple
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 early 2005, Apple released version 10.4 of Mac OS X which includes a full-featured screen reader and alternate interface named VoiceOver.
In early 2005, Serotek Corporation, makers of FreedomBox (http://www.freedombox.info/), released an inexpensive Windows screen reader called FreedomBox System Access. System Access provides access to more applications than Narrator, including Microsoft Word, Internet Explorer, and Outlook Express; but it isn't a fully-fledged screen reader like JAWS or Window-Eyes.
Also in early 2005, the CLC-4-TTS and Fire Vox (http://clc-4-tts.cjb.net/) project was started to build a freeware, open-source screen reader into Firefox as a Firefox extension. It supports the use of two TTS engines: Microsoft SAPI 5 and FreeTTS. Since FreeTTS is an open source, Java based TTS engine, the CLC-4-TTS Suite, unlike most other screen readers, is a cross platform compatible solution. Charles L. Chen, the creator of CLC-4-TTS and Fire Vox, has already personally verified that it works on Windows and Mac computers; there have also been user reports that it works fine on Linux as well.
External link
- Apple: VoiceOver (http://www.apple.com/macosx/tiger/voiceover.html)