1BRLTTY(1) The BRLTTY Project BRLTTY(1)
2
6 brltty - refreshable braille display driver for Linux/Unix
7
9 brltty [option ...]
10
12 brltty is a background process (daemon) which provides access to the
13 console screen (when in text mode) for a blind person using a refresh‐
14 able braille display. It drives the braille display, and provides com‐
15 plete screen review functionality. Some speech capability has also
16 been incorporated.
17
19 Options can be passed to brltty in a number of ways. From most to
20 least influential, these are:
21 1. Command Line Options
23 2. Boot Parameters
25 3. Environment Variables (if the -E (--environment-variables) option
27 is in effect)
28 4. The Configuration File
30 5. Built-in Defaults
32 Command Line Options
34 The options are processed sequentially from left to right. If an
35 option is specified more than once, or in case of a conflict, the
36 rightmost specification takes precedence.
37 The following options are supported:
39 -a table (--attributes-table=)
41 The path to the attributes translation table. Relative paths
42 are anchored at /etc/brltty/. The .atb extension is optional.
43 The built-in default is attributes.atb.
44 -b driver,...|auto (--braille-driver=)
46 The driver for the braille display (see Driver Specification).
47 The built-in default is auto.
48 -c table (--contraction-table=)
50 The path to the contraction table. Relative paths are anchored
51 at /etc/brltty/. The .ctb extension is optional.
52 -d device,... (--braille-device=)
54 The device to which the braille display is connected. The
55 built-in default is usb:.
56 The general form of a braille device specification is quali‐
58 fier:data. For backward compatibility with earlier releases, if
59 the qualifier is omitted then serial: is assumed. The following
60 device types are supported:
61 Bluetooth
63 For a bluetooth device, specify bluez:address. The
64 address must be six two-digit hexadecimal numbers sepa‐
65 rated by colons, e.g. 01:23:45:67:89:AB.
66 Serial For a serial device, specify serial:/path/to/device. The
68 serial: qualifier is optional (for backward compatibil‐
69 ity). If a relative path is given then it's anchored at
70 /dev/ (the usual location where devices are defined on a
71 Unix-like system). The following device specifications
72 all refer to the primary serial device: serial:/dev/,
73 serial:, /dev/, .
74 USB For a USB device, specify usb:. brltty will search for
76 the first USB device which matches the braille display
77 driver being used. If this is inadequate, e.g. if you
78 have more than one USB braille display which requires the
79 same driver, then you can refine the device specification
80 by appending the serial number of the display to it, e.g.
81 usb:12345. N.B.: The "identification by serial number"
82 feature doesn't work for some models because some manu‐
83 facturers either don't set the USB serial number descrip‐
84 tor at all or do set it but not to a unique value.
85 A comma-delimited list of braille devices may be specified. If
87 this is done then autodetection is performed on each listed
88 device in sequence. This feature is particularly useful if you
89 have a braille display with more than one interrface, e.g. both
90 a serial and a USB port.
91 -e (--standard-error)
93 Write logs to standard error rather than to the system log (use‐
94 ful for debugging).
95 -f file (--configuration-file=)
97 The path to the configuration file. Relative paths are anchored
98 at the current working directory. The built-in default is
99 /etc/brltty.conf.
100 -h (--help)
102 Print a command line usage summary and then exit.
103 -l level (--log-level=)
105 The minimum severity level for messages written to the log. Any
106 of the following numbers, or any abbreviation of their corre‐
107 sponding names, may be specified:
108 0 emergency
110 1 alert
112 2 critical
114 3 error
116 4 warning
118 5 notice
120 6 information
122 7 debug
124 The built-in default is notice.
126 -m device (--midi-device=)
128 The device to use for the Musical Instrument Digital Interface.
129 For ALSA it's client:port, where each may be either a number or
130 a case-sensitive substring of its name. For other interfaces
131 it's the full path to an appropriate system device. The built-
132 in default is:
133 Linux/ALSA the first available MIDI output port
135 Linux/OSS /dev/sequencer
137 -n (--no-daemon)
139 Remain in the foreground (useful for debugging).
140 -p device (--pcm-device=)
142 The device to use for digital audio. For ALSA it's name[:argu‐
143 ment,...]. For other interfaces it's the full path to an appro‐
144 priate system device. The built-in default is:
145 FreeBSD /dev/dsp
147 Linux/ALSA hw:0,0
149 Linux/OSS /dev/dsp
151 NetBSD /dev/audio
153 OpenBSD /dev/audio
155 Qnx the preferred PCM output device
157 Solaris /dev/audio
159 -q (--quiet)
161 Suppress the start-up messages. This is done by reducing the
162 default log level (see the -l (--log-level=) option) to warning
163 (information if either -v (--verify) or -V (--version) is also
164 specified).
165 -r (--release-device)
167 Release the device to which the braille display is connected
168 when the current screen or window can't be read.
169 -s driver,...|auto (--speech-driver=)
171 The driver for the speech synthesizer (see Driver Specifica‐
172 tion). The built-in default is auto.
173 -t table (--text-table=)
175 The path to the text translation table. Relative paths are
176 anchored at /etc/brltty/. The .ttb extension is optional. The
177 built-in default is nabcc.ttb (the North American Braille Com‐
178 puter Code).
179 -v (--verify)
181 Print the start-up messages and then exit. This always includes
182 the versions of brltty itself, the server side of its applica‐
183 tion programming interface, and each of the selected braille and
184 speech drivers. If the -q (--quiet) option isn't also specified
185 then it also includes the values of the options after all
186 sources have been considered. If more than one braille driver
187 and/or more than one braille device has been specified then
188 braille display autodetection is performed. If more than one
189 speech driver has been specified then speech synthesizer autode‐
190 tection is performed.
191 -x driver (--screen-driver=)
193 The screen driver. The built-in default is operating system
194 appropriate.
195 -A name=value,... (--api-parameters=)
197 Parameters for the application programming interface. If the
198 same parameter is specified more than once then the rightmost
199 specification is used. Parameter names may be abbreviated.
200 -B [driver:]name=value,... (--braille-parameters=)
202 Parameters for the braille display driver. If the same parame‐
203 ter is specified more than once then the rightmost specification
204 is used. Parameter names may be abbreviated. If a parameter
205 assignment is qualified with a driver identification code then
206 it's only processed if that braille display driver is being
207 used.
208 -E (--environment-variables)
210 Recognize environment variables.
211 -F fifo (--speech-fifo=)
213 The FIFO which gives other applications access to brltty's
214 speech driver. It's created at start-up and removed at termina‐
215 tion. Relative paths are anchored at /etc/brltty/. The built-
216 in default is that no FIFO is created.
217 -I (--install-service)
219 (Windows only) Install brltty as the BrlAPI service so that it
220 will be automatically started when the system is booted and so
221 that applications can know that a BrlAPI server is running.
222 -M csecs (--message-delay=)
224 The message hold time in hundredths of a second. The built-in
225 default is 400 (4 seconds).
226 -N (--no-api)
228 Don't start the application programming interface.
229 -P file (--pid-file=)
231 The full path to the process identifier file. If this option is
232 supplied, brltty writes its process identifier (pid) into the
233 specified file at start-up. The file is removed when brltty
234 terminates.
235 -R (--remove-service)
237 (Windows only) Remove the BrlAPI service so that brltty will not
238 be automatically started when the system is booted and so that
239 applications can know that no BrlAPI server is running.
240 -S [driver:]name=value,... (--speech-parameters=)
242 Parameters for the speech synthesizer driver. If the same
243 parameter is specified more than once then the rightmost speci‐
244 fication is used. Parameter names may be abbreviated. If a
245 parameter assignment is qualified with a driver identification
246 code then it's only processed if that speech synthesizer driver
247 is being used.
248 -U csecs (--update-interval=)
250 The braille window update interval in hundredths of a second.
251 The built-in default is 4 (25 times per second).
252 -V (--version)
254 Print the versions of brltty itself, the server side of its
255 application programming interface, and those drivers which were
256 configured in at build-time, and then exit. If the -q (--quiet)
257 option isn't also specified then also print copyright informa‐
258 tion.
259 -X name=value,... (--screen-parameters=)
261 Parameters for the screen driver. If the same parameter is
262 specified more than once then the rightmost specification is
263 used. Parameter names may be abbreviated.
264 Environment Variables
266 The following environment variables are recognized if the -E (--envi‐
267 ronment-variables) option is specified:
268 BRLTTY_API_PARAMETERS=name=value,...
270 Parameters for the application programming interface. See the
271 -A (--api-parameters=) option for details.
272 BRLTTY_ATTRIBUTES_TABLE=table
274 The attributes translation table. See the -a (--attributes-ta‐
275 ble=) option for details.
276 BRLTTY_BRAILLE_DEVICE=device,...
278 The device to which the braille display is connected. See the
279 -d (--braille-device=) option for details.
280 BRLTTY_BRAILLE_DRIVER=driver,...|auto
282 The driver for the braille display. See the -b (--braille-
283 driver=) option for details.
284 BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
286 Parameters for the braille display driver. See the -B
287 (--braille-parameters=) option for details.
288 BRLTTY_CONFIGURATION_FILE=file
290 The configuration file. See the -f (--configuration-file=)
291 option for details.
292 BRLTTY_CONTRACTION_TABLE=table
294 The contraction table. See the -c (--contraction-table=) option
295 for details.
296 BRLTTY_MIDI_DEVICE=device
298 The device to use for the Musical Instrument Digital Interface.
299 See the -m (--midi-device=) option for details.
300 BRLTTY_PCM_DEVICE=device
302 The device to use for digital audio. See the -p (--pcm-device=)
303 option for details.
304 BRLTTY_RELEASE_DEVICE=on|off
306 Release the device to which the braille display is connected
307 when the current screen or window can't be read. See the -r
308 (--release-device) option for details.
309 BRLTTY_SCREEN_DRIVER=driver
311 The screen driver. See the -x (--screen-driver=) option for
312 details.
313 BRLTTY_SCREEN_PARAMETERS=name=value,...
315 Parameters for the screen driver. See the -X (--screen-parame‐
316 ters=) option for details.
317 BRLTTY_SPEECH_DRIVER=driver,...|auto
319 The driver for the speech synthesizer. See the -s (--speech-
320 driver=) option for details.
321 BRLTTY_SPEECH_FIFO=fifo
323 The FIFO which gives other applications access to brltty's
324 speech driver. See the -F (--speech-fifo=) option for details.
325 BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
327 Parameters for the speech synthesizer driver. See the -S
328 (--speech-parameters=) option for details.
329 BRLTTY_TEXT_TABLE=table
331 The text translation table. See the -t (--text-table=) option
332 for details.
333 The Configuration File
335 Blank lines are ignored. If the character # occurs on any line then
336 all characters from it to the end of that line are treated as a com‐
337 ment.
338 The following configuration directives are supported:
340 api-parameters name=value,...
342 Parameters for the application programming interface. See the
343 -A (--api-parameters=) option for details.
344 attributes-table table
346 The attributes translation table. See the -a (--attributes-ta‐
347 ble=) option for details.
348 braille-device device,...
350 The device to which the braille display is connected. See the
351 -d (--braille-device=) option for details.
352 braille-driver driver,...|auto
354 The driver for the braille display. See the -b (--braille-
355 driver=) option for details.
356 braille-parameters [driver:]name=value,...
358 Parameters for the braille display driver. See the -B
359 (--braille-parameters=) option for details.
360 contraction-table table
362 The contraction table. See the -c (--contraction-table=) option
363 for details.
364 midi-device device
366 The device to use for the Musical Instrument Digital Interface.
367 See the -m (--midi-device=) option for details.
368 pcm-device device
370 The device to use for digital audio. See the -p (--pcm-device=)
371 option for details.
372 release-device on|off
374 Release the device to which the braille display is connected
375 when the current screen or window can't be read. See the -r
376 (--release-device) option for details.
377 screen-driver driver
379 The screen driver. See the -x (--screen-driver=) option for
380 details.
381 screen-parameters name=value,...
383 Parameters for the screen driver. See the -X (--screen-parame‐
384 ters=) option for details.
385 speech-driver driver,...|auto
387 The driver for the speech synthesizer. See the -s (--speech-
388 driver=) option for details.
389 speech-fifo fifo
391 The FIFO which gives other applications access to brltty's
392 speech driver. See the -F (--speech-fifo=) option for details.
393 speech-parameters [driver:]name=value,...
395 Parameters for the speech synthesizer driver. See the -S
396 (--speech-parameters=) option for details.
397 text-table table
399 The text translation table. See the -t (--text-table=) option
400 for details.
401 Driver Specification
403 A braille display or speech synthesizer driver must be specified via
404 its identification code:
405 al Alva
407 at Albatross
409 ba BrlAPI
411 bd Braudi
413 bl BrailleLite
415 bm Baum
417 bn BrailleNote
419 cb CombiBraille
421 ec EcoBraille
423 es ExternalSpeech
425 eu EuroBraille
427 fl FestivalLite
429 fs FreedomScientific
431 fv Festival
433 gs GenericSay
435 hm HIMS
437 ht HandyTech
439 il IrisLinux
441 lb Libbraille
443 lt LogText
445 mb MultiBraille
447 md MDV
449 mn MiniBraille
451 mp Mikropuhe
453 no no driver
455 pg Pegasus
457 pm Papenmeier
459 sd SpeechDispatcher
461 sk Seika
463 sw Swift
465 th Theta
467 tn TechniBraille Systems Inc.
469 ts Telesensory Systems Inc.
471 tt TTY
473 vd VideoBraille
475 vo Voyager
477 vr Virtual
479 vs VisioBraille
481 vv ViaVoice
483 xw XWindow
485 A comma-delimited list of drivers may be specified. If this is
487 done then autodetection is performed using each listed driver in
488 sequence. You may need to experiment in order to determine the
489 most reliable order since some drivers autodetect better than
490 others.
491 If the single word auto is specified then autodetection is per‐
493 formed using only those drivers which are known to be reliable
494 for this purpose.
495
497 For full documentation, see brltty's on-line manual at
498 [http://mielke.cc/brltty/doc/Manual-HTML/Manual.html].
499brltty 4.1 October 2009 BRLTTY(1)