1BRLTTY(1) BRLTTY User's Manual BRLTTY(1)
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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 -p device (--pcm-device=)
155 The device to use for digital audio. For ALSA it's name[:argu‐
156 ment,...]. For other interfaces it's the full path to an appro‐
157 priate system device. The built-in default is:
158 FreeBSD /dev/dsp
160 Linux/ALSA hw:0,0
162 Linux/OSS /dev/dsp
164 NetBSD /dev/audio
166 OpenBSD /dev/audio
168 Qnx the preferred PCM output device
170 Solaris /dev/audio
172 -q (--quiet)
174 Suppress the start-up messages. This is done by reducing the
175 default log level (see the -l (--log-level=) option) to warning
176 (information if either -v (--verify) or -V (--version) is also
177 specified).
178 -r (--release-device)
180 Release the device to which the braille display is connected
181 when the current screen or window can't be read.
182 -s driver,...|auto (--speech-driver=)
184 The driver for the speech synthesizer (see Driver Specifica‐
185 tion). The built-in default is auto.
186 -t table (--text-table=)
188 The path to the text table. Relative paths are anchored at
189 /etc/brltty/Text. The .ttb extension is optional. The built-in
190 default is en-nabcc.ttb (the North American Braille Computer
191 Code).
192 -v (--verify)
194 Print the start-up messages and then exit. This always includes
195 the versions of brltty itself, the server side of its applica‐
196 tion programming interface, and each of the selected braille and
197 speech drivers. If the -q (--quiet) option isn't also specified
198 then it also includes the values of the options after all
199 sources have been considered. If more than one braille driver
200 and/or more than one braille device has been specified then
201 braille display autodetection is performed. If more than one
202 speech driver has been specified then speech synthesizer autode‐
203 tection is performed.
204 -x driver (--screen-driver=)
206 The screen driver. The built-in default is operating system
207 appropriate.
208 -A name=value,... (--api-parameters=)
210 Parameters for the application programming interface. If the
211 same parameter is specified more than once then the rightmost
212 specification is used. Parameter names may be abbreviated.
213 -B [driver:]name=value,... (--braille-parameters=)
215 Parameters for the braille display driver. If the same parame‐
216 ter is specified more than once then the rightmost specification
217 is used. Parameter names may be abbreviated. If a parameter
218 assignment is qualified with a driver identification code then
219 it's only processed if that braille display driver is being
220 used.
221 -D directory (--drivers-directory=)
223 The path to the directory which contains the dynamically load‐
224 able driver objects. The built-in default is /usr/lib64/brltty.
225 -E (--environment-variables)
227 Recognize environment variables.
228 -F file (--preferences-file=)
230 The path to the preferences file. Relative paths are anchored
231 at /var/lib/brltty. The built-in default is brltty.prefs.
232 -H (--full-help)
234 Print a command line usage summary (all options), and then exit.
235 -I (--install-service)
237 (Windows only) Install brltty as the BrlAPI service so that it
238 will be automatically started when the system is booted, and so
239 that applications can know that a BrlAPI server is running.
240 -K arg (--keyboard-properties=)
242 Properties of the keyboard.
243 -L file (--log-file=)
245 The file to which log messages are written. Relative paths are
246 anchored at the current working directory. The default is to
247 send log messages to the system log.
248 -M csecs (--message-delay=)
250 The message hold time in hundredths of a second. The built-in
251 default is 400 (4 seconds).
252 -N (--no-api)
254 Don't start the application programming interface.
255 -P file (--pid-file=)
257 The full path to the process identifier file. If this option is
258 supplied, brltty writes its process identifier (pid) into the
259 specified file at start-up. The file is removed when brltty
260 terminates.
261 -R (--remove-service)
263 (Windows only) Remove the BrlAPI service so that brltty will not
264 be automatically started when the system is booted, and so that
265 applications can know that no BrlAPI server is running.
266 -S [driver:]name=value,... (--speech-parameters=)
268 Parameters for the speech synthesizer driver. If the same
269 parameter is specified more than once then the rightmost speci‐
270 fication is used. Parameter names may be abbreviated. If a
271 parameter assignment is qualified with a driver identification
272 code then it's only processed if that speech synthesizer driver
273 is being used.
274 -T directory (--tables-directory=)
276 The path to the directory which contains the text, attributes,
277 contraction, keyboard, and input tables. The built-in default
278 is /etc/brltty.
279 -U directory (--updatable-directory=)
281 The path to a directory which contains files that can be
282 updated. The built-in default is /var/lib/brltty.
283 -V (--version)
285 Print the versions of brltty itself, the server side of its
286 application programming interface, and those drivers which were
287 configured in at build-time, and then exit. If the -q (--quiet)
288 option isn't also specified then also print copyright informa‐
289 tion.
290 -W directory (--writable-directory=)
292 The path to a directory which can be written to. The built-in
293 default is /var/run/brltty.
294 -X name=value,... (--screen-parameters=)
296 Parameters for the screen driver. If the same parameter is
297 specified more than once then the rightmost specification is
298 used. Parameter names may be abbreviated.
299 -Y text (--start-message=)
301 The text to be shown when the braille driver starts and to be
302 spoken when the speech driver starts. The built-in default is
303 BRLTTY 6.0.
304 -Z text (--stop-message=)
306 The text to be shown when the braille driver stops. The built-
307 in default is BRLTTY stopped.
308 Environment Variables
310 The following environment variables are recognized if the -E (--envi‐
311 ronment-variables) option is specified:
312 BRLTTY_API_PARAMETERS=name=value,...
314 Parameters for the application programming interface. See the
315 -A (--api-parameters=) option for details.
316 BRLTTY_ATTRIBUTES_TABLE=table
318 The attributes table. See the -a (--attributes-table=) option
319 for details.
320 BRLTTY_BRAILLE_DEVICE=device,...
322 The device to which the braille display is connected. See the
323 -d (--braille-device=) option for details.
324 BRLTTY_BRAILLE_DRIVER=driver,...|auto
326 The driver for the braille display. See the -b
327 (--braille-driver=) option for details.
328 BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
330 Parameters for the braille display driver. See the -B
331 (--braille-parameters=) option for details.
332 BRLTTY_CONFIGURATION_FILE=file
334 The configuration file. See the -f (--configuration-file=)
335 option for details.
336 BRLTTY_CONTRACTION_TABLE=table
338 The contraction table. See the -c (--contraction-table=) option
339 for details.
340 BRLTTY_MIDI_DEVICE=device
342 The device to use for the Musical Instrument Digital Interface.
343 See the -m (--midi-device=) option for details.
344 BRLTTY_PCM_DEVICE=device
346 The device to use for digital audio. See the -p (--pcm-device=)
347 option for details.
348 BRLTTY_PREFERENCES_FILE=file
350 The preferences file. See the -F (--preferences-file=) option
351 for details.
352 BRLTTY_RELEASE_DEVICE=on|off
354 Release the device to which the braille display is connected
355 when the current screen or window can't be read. See the -r
356 (--release-device) option for details.
357 BRLTTY_SCREEN_DRIVER=driver
359 The screen driver. See the -x (--screen-driver=) option for
360 details.
361 BRLTTY_SCREEN_PARAMETERS=name=value,...
363 Parameters for the screen driver. See the -X (--screen-parame‐
364 ters=) option for details.
365 BRLTTY_SPEECH_DRIVER=driver,...|auto
367 The driver for the speech synthesizer. See the -s
368 (--speech-driver=) option for details.
369 BRLTTY_SPEECH_INPUT=name
371 The file system object which gives other applications access to
372 brltty's speech driver for text-to-speech conversion. See the
373 -i (--speech-input=) option for details.
374 BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
376 Parameters for the speech synthesizer driver. See the -S
377 (--speech-parameters=) option for details.
378 BRLTTY_TEXT_TABLE=table
380 The text table. See the -t (--text-table=) option for details.
381 The Configuration File
383 Blank lines are ignored. If the character # occurs on any line then
384 all characters from it to the end of that line are treated as a com‐
385 ment.
386 The following configuration directives are supported:
388 api-parameters name=value,...
390 Parameters for the application programming interface. See the
391 -A (--api-parameters=) option for details.
392 attributes-table table
394 The attributes table. See the -a (--attributes-table=) option
395 for details.
396 braille-device device,...
398 The device to which the braille display is connected. See the
399 -d (--braille-device=) option for details.
400 braille-driver driver,...|auto
402 The driver for the braille display. See the -b
403 (--braille-driver=) option for details.
404 braille-parameters [driver:]name=value,...
406 Parameters for the braille display driver. See the -B
407 (--braille-parameters=) option for details.
408 contraction-table table
410 The contraction table. See the -c (--contraction-table=) option
411 for details.
412 midi-device device
414 The device to use for the Musical Instrument Digital Interface.
415 See the -m (--midi-device=) option for details.
416 pcm-device device
418 The device to use for digital audio. See the -p (--pcm-device=)
419 option for details.
420 preferences-file file
422 The preferences file. See the -F (--preferences-file=) option
423 for details.
424 release-device on|off
426 Release the device to which the braille display is connected
427 when the current screen or window can't be read. See the -r
428 (--release-device) option for details.
429 screen-driver driver
431 The screen driver. See the -x (--screen-driver=) option for
432 details.
433 screen-parameters name=value,...
435 Parameters for the screen driver. See the -X (--screen-parame‐
436 ters=) option for details.
437 speech-driver driver,...|auto
439 The driver for the speech synthesizer. See the -s
440 (--speech-driver=) option for details.
441 speech-input 0me
443 The file system object which gives other applications access to
444 brltty's speech driver for text-to-speech conversion. See the
445 -i (--speech-input=) option for details.
446 speech-parameters [driver:]name=value,...
448 Parameters for the speech synthesizer driver. See the -S
449 (--speech-parameters=) option for details.
450 text-table table
452 The text table. See the -t (--text-table=) option for details.
453 Driver Specification
455 A braille display or speech synthesizer driver must be specified via
456 its identification code:
457 al Alva
459 an Android
461 at Albatross
463 ba BrlAPI
465 bc BrailComm
467 bd Braudi
469 bg B2G
471 bl BrailleLite
473 bm Baum
475 bn BrailleNote
477 cb CombiBraille
479 ec EcoBraille
481 en eSpeak-NG
483 es eSpeak
485 eu EuroBraille
487 fl FestivalLite
489 fs FreedomScientific
491 fv Festival
493 gs GenericSay
495 hd Hedo
497 hm HIMS
499 ht HandyTech
501 hw HumanWare
503 ir Iris
505 ic Inceptor
507 lb Libbraille
509 lt LogText
511 mb MultiBraille
513 md MDV
515 mm BrailleMemo
517 mn MiniBraille
519 mp Mikropuhe
521 mt Metec
523 no no driver
525 np NinePoint
527 pg Pegasus
529 pm Papenmeier
531 sd SpeechDispatcher
533 sk Seika
535 sw Swift
537 th Theta
539 tn TechniBraille Systems Inc.
541 ts Telesensory Systems Inc.
543 tt TTY
545 vd VideoBraille
547 vo Voyager, Part232 (serial adapter), BraillePen/EasyLink
549 vr Virtual
551 vs VisioBraille
553 vv ViaVoice
555 xs ExternalSpeech
557 xw XWindow
559 A comma-delimited list of drivers may be specified. If this is
561 done then autodetection is performed using each listed driver in
562 sequence. You may need to experiment in order to determine the
563 most reliable order since some drivers autodetect better than
564 others.
565 If the single word auto is specified then autodetection is per‐
567 formed using only those drivers which are known to be reliable
568 for this purpose.
569
571 For full documentation, see brltty's on-line manual at
572 [http://brltty.app/documentation.html].
573brltty 6.0 2019-02-22 BRLTTY(1)