1BRLTTY(1) BRLTTY User's Manual 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 table. Relative paths are anchored
42 at /etc/brltty/Attributes. The .atb extension is optional. The
43 built-in default is left_right.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/Contraction. 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:,bluetooth:.
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 bluetooth: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:device. The serial:
68 qualifier is optional (for backward compatibility). If a
69 relative path is given then it's anchored at /dev/ (the
70 usual location where devices are defined on a Unix-like
71 system). The following device specifications all refer
72 to the primary serial device on Linux: serial:ttyS0,
73 serial:/dev/ttyS0, ttyS0, /dev/ttyS0.
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 interface, e.g. both a
90 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 (commonly used options only),
103 and then exit.
104 -i name (--speech-input=)
106 The file system object (FIFO, named pipe, named socket, etc)
107 which gives other applications access to brltty's speech driver
108 for text-to-speech conversion. It's created at start-up and
109 removed at termination. Relative paths are anchored at the cur‐
110 rent working directory. The built-in default is that the file
111 system object is not created.
112 -k table (--keyboard-table=)
114 The path to the keyboard table. Relative paths are anchored at
115 /etc/brltty/Keyboard. The .ktb extension is optional.
116 -l level (--log-level=)
118 The minimum severity level for messages written to the log. Any
119 of the following numbers, or any abbreviation of their corre‐
120 sponding names, may be specified:
121 0 emergency
123 1 alert
125 2 critical
127 3 error
129 4 warning
131 5 notice
133 6 information
135 7 debug
137 The built-in default is notice.
139 -m device (--midi-device=)
141 The device to use for the Musical Instrument Digital Interface.
142 For ALSA it's client:port, where each may be either a number or
143 a case-sensitive substring of its name. For other interfaces
144 it's the full path to an appropriate system device. The built-
145 in default is:
146 Linux/ALSA the first available MIDI output port
148 Linux/OSS /dev/sequencer
150 -n (--no-daemon)
152 Remain in the foreground (useful for debugging).
153 -o name=value,... (--override-preference=)
155 Explicit preference settings.
156 -p device (--pcm-device=)
158 The device to use for digital audio. For ALSA it's name[:argu‐
159 ment,...]. For other interfaces it's the full path to an appro‐
160 priate system device. The built-in default is:
161 FreeBSD /dev/dsp
163 Linux/ALSA hw:0,0
165 Linux/OSS /dev/dsp
167 NetBSD /dev/audio
169 OpenBSD /dev/audio
171 Qnx the preferred PCM output device
173 Solaris /dev/audio
175 -q (--quiet)
177 Suppress the start-up messages. This is done by reducing the
178 default log level (see the -l (--log-level=) option) to warning
179 (information if either -v (--verify) or -V (--version) is also
180 specified).
181 -r (--release-device)
183 Release the device to which the braille display is connected
184 when the current screen or window can't be read.
185 -s driver,...|auto (--speech-driver=)
187 The driver for the speech synthesizer (see Driver Specifica‐
188 tion). The built-in default is auto.
189 -t table (--text-table=)
191 The path to the text table. Relative paths are anchored at
192 /etc/brltty/Text. The .ttb extension is optional. The built-in
193 default is en-nabcc.ttb (the North American Braille Computer
194 Code).
195 -v (--verify)
197 Print the start-up messages and then exit. This always includes
198 the versions of brltty itself, the server side of its applica‐
199 tion programming interface, and each of the selected braille and
200 speech drivers. If the -q (--quiet) option isn't also specified
201 then it also includes the values of the options after all
202 sources have been considered. If more than one braille driver
203 and/or more than one braille device has been specified then
204 braille display autodetection is performed. If more than one
205 speech driver has been specified then speech synthesizer autode‐
206 tection is performed.
207 -x driver (--screen-driver=)
209 The screen driver. The built-in default is operating system
210 appropriate.
211 -A name=value,... (--api-parameters=)
213 Parameters for the application programming interface. If the
214 same parameter is specified more than once then the rightmost
215 specification is used. Parameter names may be abbreviated.
216 -B [driver:]name=value,... (--braille-parameters=)
218 Parameters for the braille display driver. If the same parame‐
219 ter is specified more than once then the rightmost specification
220 is used. Parameter names may be abbreviated. If a parameter
221 assignment is qualified with a driver identification code then
222 it's only processed if that braille display driver is being
223 used.
224 -D directory (--drivers-directory=)
226 The path to the directory which contains the dynamically load‐
227 able driver objects. The built-in default is /usr/lib64/brltty.
228 -E (--environment-variables)
230 Recognize environment variables.
231 -F file (--preferences-file=)
233 The path to the preferences file. Relative paths are anchored
234 at /var/lib/brltty. The built-in default is brltty.prefs.
235 -H (--full-help)
237 Print a command line usage summary (all options), and then exit.
238 -I (--install-service)
240 (Windows only) Install brltty as the BrlAPI service so that it
241 will be automatically started when the system is booted, and so
242 that applications can know that a BrlAPI server is running.
243 -K arg (--keyboard-properties=)
245 Properties of the keyboard.
246 -L file (--log-file=)
248 The file to which log messages are written. Relative paths are
249 anchored at the current working directory. The default is to
250 send log messages to the system log.
251 -M csecs (--message-delay=)
253 The message hold time in hundredths of a second. The built-in
254 default is 400 (4 seconds).
255 -N (--no-api)
257 Don't start the application programming interface.
258 -P file (--pid-file=)
260 The full path to the process identifier file. If this option is
261 supplied, brltty writes its process identifier (pid) into the
262 specified file at start-up. The file is removed when brltty
263 terminates.
264 -R (--remove-service)
266 (Windows only) Remove the BrlAPI service so that brltty will not
267 be automatically started when the system is booted, and so that
268 applications can know that no BrlAPI server is running.
269 -S [driver:]name=value,... (--speech-parameters=)
271 Parameters for the speech synthesizer driver. If the same
272 parameter is specified more than once then the rightmost speci‐
273 fication is used. Parameter names may be abbreviated. If a
274 parameter assignment is qualified with a driver identification
275 code then it's only processed if that speech synthesizer driver
276 is being used.
277 -T directory (--tables-directory=)
279 The path to the directory which contains the text, attributes,
280 contraction, keyboard, and input tables. The built-in default
281 is /etc/brltty.
282 -U directory (--updatable-directory=)
284 The path to a directory which contains files that can be
285 updated. The built-in default is /var/lib/brltty.
286 -V (--version)
288 Print the versions of brltty itself, the server side of its
289 application programming interface, and those drivers which were
290 configured in at build-time, and then exit. If the -q (--quiet)
291 option isn't also specified then also print copyright informa‐
292 tion.
293 -W directory (--writable-directory=)
295 The path to a directory which can be written to. The built-in
296 default is /var/run/brltty.
297 -X name=value,... (--screen-parameters=)
299 Parameters for the screen driver. If the same parameter is
300 specified more than once then the rightmost specification is
301 used. Parameter names may be abbreviated.
302 -Y text (--start-message=)
304 The text to be shown when the braille driver starts and to be
305 spoken when the speech driver starts. The built-in default is
306 BRLTTY 6.1.
307 -Z text (--stop-message=)
309 The text to be shown when the braille driver stops. The built-
310 in default is BRLTTY stopped.
311 Environment Variables
313 The following environment variables are recognized if the -E (--envi‐
314 ronment-variables) option is specified:
315 BRLTTY_API_PARAMETERS=name=value,...
317 Parameters for the application programming interface. See the
318 -A (--api-parameters=) option for details.
319 BRLTTY_ATTRIBUTES_TABLE=table
321 The attributes table. See the -a (--attributes-table=) option
322 for details.
323 BRLTTY_BRAILLE_DEVICE=device,...
325 The device to which the braille display is connected. See the
326 -d (--braille-device=) option for details.
327 BRLTTY_BRAILLE_DRIVER=driver,...|auto
329 The driver for the braille display. See the -b
330 (--braille-driver=) option for details.
331 BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
333 Parameters for the braille display driver. See the -B
334 (--braille-parameters=) option for details.
335 BRLTTY_CONFIGURATION_FILE=file
337 The configuration file. See the -f (--configuration-file=)
338 option for details.
339 BRLTTY_CONTRACTION_TABLE=table
341 The contraction table. See the -c (--contraction-table=) option
342 for details.
343 BRLTTY_MIDI_DEVICE=device
345 The device to use for the Musical Instrument Digital Interface.
346 See the -m (--midi-device=) option for details.
347 BRLTTY_PCM_DEVICE=device
349 The device to use for digital audio. See the -p (--pcm-device=)
350 option for details.
351 BRLTTY_PREFERENCES_FILE=file
353 The preferences file. See the -F (--preferences-file=) option
354 for details.
355 BRLTTY_RELEASE_DEVICE=on|off
357 Release the device to which the braille display is connected
358 when the current screen or window can't be read. See the -r
359 (--release-device) option for details.
360 BRLTTY_SCREEN_DRIVER=driver
362 The screen driver. See the -x (--screen-driver=) option for
363 details.
364 BRLTTY_SCREEN_PARAMETERS=name=value,...
366 Parameters for the screen driver. See the -X (--screen-parame‐
367 ters=) option for details.
368 BRLTTY_SPEECH_DRIVER=driver,...|auto
370 The driver for the speech synthesizer. See the -s
371 (--speech-driver=) option for details.
372 BRLTTY_SPEECH_INPUT=name
374 The file system object which gives other applications access to
375 brltty's speech driver for text-to-speech conversion. See the
376 -i (--speech-input=) option for details.
377 BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
379 Parameters for the speech synthesizer driver. See the -S
380 (--speech-parameters=) option for details.
381 BRLTTY_TEXT_TABLE=table
383 The text table. See the -t (--text-table=) option for details.
384 The Configuration File
386 Blank lines are ignored. If the character # occurs on any line then
387 all characters from it to the end of that line are treated as a com‐
388 ment.
389 The following configuration directives are supported:
391 api-parameters name=value,...
393 Parameters for the application programming interface. See the
394 -A (--api-parameters=) option for details.
395 attributes-table table
397 The attributes table. See the -a (--attributes-table=) option
398 for details.
399 braille-device device,...
401 The device to which the braille display is connected. See the
402 -d (--braille-device=) option for details.
403 braille-driver driver,...|auto
405 The driver for the braille display. See the -b
406 (--braille-driver=) option for details.
407 braille-parameters [driver:]name=value,...
409 Parameters for the braille display driver. See the -B
410 (--braille-parameters=) option for details.
411 contraction-table table
413 The contraction table. See the -c (--contraction-table=) option
414 for details.
415 midi-device device
417 The device to use for the Musical Instrument Digital Interface.
418 See the -m (--midi-device=) option for details.
419 pcm-device device
421 The device to use for digital audio. See the -p (--pcm-device=)
422 option for details.
423 preferences-file file
425 The preferences file. See the -F (--preferences-file=) option
426 for details.
427 release-device on|off
429 Release the device to which the braille display is connected
430 when the current screen or window can't be read. See the -r
431 (--release-device) option for details.
432 screen-driver driver
434 The screen driver. See the -x (--screen-driver=) option for
435 details.
436 screen-parameters name=value,...
438 Parameters for the screen driver. See the -X (--screen-parame‐
439 ters=) option for details.
440 speech-driver driver,...|auto
442 The driver for the speech synthesizer. See the -s
443 (--speech-driver=) option for details.
444 speech-input 0me
446 The file system object which gives other applications access to
447 brltty's speech driver for text-to-speech conversion. See the
448 -i (--speech-input=) option for details.
449 speech-parameters [driver:]name=value,...
451 Parameters for the speech synthesizer driver. See the -S
452 (--speech-parameters=) option for details.
453 text-table table
455 The text table. See the -t (--text-table=) option for details.
456 Driver Specification
458 A braille display or speech synthesizer driver must be specified via
459 its identification code:
460 al Alva
462 an Android
464 at Albatross
466 ba BrlAPI
468 bc BrailComm
470 bd Braudi
472 bg B2G
474 bl BrailleLite
476 bm Baum
478 bn BrailleNote
480 cb CombiBraille
482 ce Cebra
484 cn Canute
486 ec EcoBraille
488 en eSpeak-NG
490 es eSpeak
492 eu EuroBraille
494 fl FestivalLite
496 fs FreedomScientific
498 fv Festival
500 gs GenericSay
502 hd Hedo
504 hm HIMS
506 ht HandyTech
508 hw HumanWare
510 ir Iris
512 ic Inceptor
514 lb Libbraille
516 lt LogText
518 mb MultiBraille
520 md MDV
522 mm BrailleMemo
524 mn MiniBraille
526 mp Mikropuhe
528 mt Metec
530 no no driver
532 np NinePoint
534 pg Pegasus
536 pm Papenmeier
538 sd SpeechDispatcher
540 sk Seika
542 sw Swift
544 th Theta
546 tn TechniBraille Systems Inc.
548 ts Telesensory Systems Inc.
550 tt TTY
552 vd VideoBraille
554 vo Voyager, Part232 (serial adapter), BraillePen/EasyLink
556 vr Virtual
558 vs VisioBraille
560 vv ViaVoice
562 xs ExternalSpeech
564 xw XWindow
566 A comma-delimited list of drivers may be specified. If this is
568 done then autodetection is performed using each listed driver in
569 sequence. You may need to experiment in order to determine the
570 most reliable order since some drivers autodetect better than
571 others.
572 If the single word auto is specified then autodetection is per‐
574 formed using only those drivers which are known to be reliable
575 for this purpose.
576
578 For full documentation, see brltty's on-line manual at
579 [http://brltty.app/documentation.html].
580brltty 6.1 2020-04-06 BRLTTY(1)