[Accessibility] BRLTTY Was Re: FSG102 Document Part 1 Section D working copy

Mario Lang mlang at debian.org
Tue Jul 22 11:35:52 PDT 2003

Janina and others:

brltty 3.3 (about to be released every day now) will include a API and
client library implementing it (BrlAPI) for remotely getting control over
the braille display for a certain tty.  Subsequently, braille display key
presses are delivered to the client via callbacks, and various routines for
setting display cells with and without the use of translation-tables are
This functionality exposes the numberous low-level driver implementations
for different display types provided by BRLTTY as a uniform interface
to potential braille display using applications, and promotes
reuse of existing, well-tested software components.  It also provides
a solution for the problem of many Assistive Technologies wanting
to use one braille display concurrently.  If two screen readers
want to provide braille output, and they use the same device, conflicts
occur.  The user would need to stop one, and start the other in some
way to prevent this.  This is not directly obvious for just one environment,
like a Desktop environment, but if the user wants to use the GUI
and console environments concurrently, the problem immediately starts to
By associating each client with a certain tty, BRLTTY can decide based on the
currently active tty to which of its clients it should dispatch display key
presses, and if display ccontent changing calls are allowed to affect the
This way, the actual device is only opened once, by brltty, and dispatch
of control is also provided by brltty.  BrlAPI clients can choose to
operate in a completely device independent manner, providing a very high
level abstraction of a basic refreshable braille display.  However, they
can also choose to operate in 'rawmode', utilising display type specific
characteristics if need be.

One program using this API already is gnopernicus.

I think this looks like something we should include in the standard.

Therefore, I propose the foolowing change, marking it up with <add></add>

Janina Sajka <janina at rednote.net> writes:

>  d. Existing free software projects related to the proposed standard.
>       X11R6/XFree86 (includes XKB)
>       GNOME
>       AT-SPI (GNOME) including libspi, libcspi, and AT-SPI's CORBA IDL.
>       ATK
>       gnome-mag
>       gnome-speech
>       Java Access Bridge for Gnome (LGPL license, but requires Java 1.4)
        brltty (libbrlapi)
>       gnopernicus screenreader, Gnome Onscreen Keyboard
>        (examples of ATs written to standard APIs)
> Speakup
> Brltty
> Emacspeak
> Console508
> -- 
> 				Janina Sajka, Director
> 				Technology Research and Development
> 				Governmental Relations Group
> 				American Foundation for the Blind (AFB)
> Email: janina at afb.net		Phone: (202) 408-8175
> _______________________________________________
> Accessibility mailing list
> Accessibility at freestandards.org
> http://www.freestandards.org/cgi-bin/mailman/listinfo/accessibility

  Mario | Debian Developer <URL:http://debian.org/>
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