1BRLTTY(1) BRLTTY User's Manual BRLTTY(1)
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6 brltty - refreshable braille display driver for Linux/Unix
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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 Environment Variables
301 The following environment variables are recognized if the -E (--envi‐
302 ronment-variables) option is specified:
303 BRLTTY_API_PARAMETERS=name=value,...
305 Parameters for the application programming interface. See the
306 -A (--api-parameters=) option for details.
307 BRLTTY_ATTRIBUTES_TABLE=table
309 The attributes table. See the -a (--attributes-table=) option
310 for details.
311 BRLTTY_BRAILLE_DEVICE=device,...
313 The device to which the braille display is connected. See the
314 -d (--braille-device=) option for details.
315 BRLTTY_BRAILLE_DRIVER=driver,...|auto
317 The driver for the braille display. See the -b
318 (--braille-driver=) option for details.
319 BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
321 Parameters for the braille display driver. See the -B
322 (--braille-parameters=) option for details.
323 BRLTTY_CONFIGURATION_FILE=file
325 The configuration file. See the -f (--configuration-file=)
326 option for details.
327 BRLTTY_CONTRACTION_TABLE=table
329 The contraction table. See the -c (--contraction-table=) option
330 for details.
331 BRLTTY_MIDI_DEVICE=device
333 The device to use for the Musical Instrument Digital Interface.
334 See the -m (--midi-device=) option for details.
335 BRLTTY_PCM_DEVICE=device
337 The device to use for digital audio. See the -p (--pcm-device=)
338 option for details.
339 BRLTTY_PREFERENCES_FILE=file
341 The preferences file. See the -F (--preferences-file=) option
342 for details.
343 BRLTTY_RELEASE_DEVICE=on|off
345 Release the device to which the braille display is connected
346 when the current screen or window can't be read. See the -r
347 (--release-device) option for details.
348 BRLTTY_SCREEN_DRIVER=driver
350 The screen driver. See the -x (--screen-driver=) option for
351 details.
352 BRLTTY_SCREEN_PARAMETERS=name=value,...
354 Parameters for the screen driver. See the -X (--screen-parame‐
355 ters=) option for details.
356 BRLTTY_SPEECH_DRIVER=driver,...|auto
358 The driver for the speech synthesizer. See the -s
359 (--speech-driver=) option for details.
360 BRLTTY_SPEECH_INPUT=name
362 The file system object which gives other applications access to
363 brltty's speech driver for text-to-speech conversion. See the
364 -i (--speech-input=) option for details.
365 BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
367 Parameters for the speech synthesizer driver. See the -S
368 (--speech-parameters=) option for details.
369 BRLTTY_TEXT_TABLE=table
371 The text table. See the -t (--text-table=) option for details.
372 The Configuration File
374 Blank lines are ignored. If the character # occurs on any line then
375 all characters from it to the end of that line are treated as a com‐
376 ment.
377 The following configuration directives are supported:
379 api-parameters name=value,...
381 Parameters for the application programming interface. See the
382 -A (--api-parameters=) option for details.
383 attributes-table table
385 The attributes table. See the -a (--attributes-table=) option
386 for details.
387 braille-device device,...
389 The device to which the braille display is connected. See the
390 -d (--braille-device=) option for details.
391 braille-driver driver,...|auto
393 The driver for the braille display. See the -b
394 (--braille-driver=) option for details.
395 braille-parameters [driver:]name=value,...
397 Parameters for the braille display driver. See the -B
398 (--braille-parameters=) option for details.
399 contraction-table table
401 The contraction table. See the -c (--contraction-table=) option
402 for details.
403 midi-device device
405 The device to use for the Musical Instrument Digital Interface.
406 See the -m (--midi-device=) option for details.
407 pcm-device device
409 The device to use for digital audio. See the -p (--pcm-device=)
410 option for details.
411 preferences-file file
413 The preferences file. See the -F (--preferences-file=) option
414 for details.
415 release-device on|off
417 Release the device to which the braille display is connected
418 when the current screen or window can't be read. See the -r
419 (--release-device) option for details.
420 screen-driver driver
422 The screen driver. See the -x (--screen-driver=) option for
423 details.
424 screen-parameters name=value,...
426 Parameters for the screen driver. See the -X (--screen-parame‐
427 ters=) option for details.
428 speech-driver driver,...|auto
430 The driver for the speech synthesizer. See the -s
431 (--speech-driver=) option for details.
432 speech-input 0me
434 The file system object which gives other applications access to
435 brltty's speech driver for text-to-speech conversion. See the
436 -i (--speech-input=) option for details.
437 speech-parameters [driver:]name=value,...
439 Parameters for the speech synthesizer driver. See the -S
440 (--speech-parameters=) option for details.
441 text-table table
443 The text table. See the -t (--text-table=) option for details.
444 Driver Specification
446 A braille display or speech synthesizer driver must be specified via
447 its identification code:
448 al Alva
450 an Android
452 at Albatross
454 ba BrlAPI
456 bc BrailComm
458 bd Braudi
460 bg B2G
462 bl BrailleLite
464 bm Baum
466 bn BrailleNote
468 cb CombiBraille
470 ec EcoBraille
472 en eSpeak-NG
474 es eSpeak
476 eu EuroBraille
478 fl FestivalLite
480 fs FreedomScientific
482 fv Festival
484 gs GenericSay
486 hd Hedo
488 hm HIMS
490 ht HandyTech
492 hw HumanWare
494 ir Iris
496 ic Inceptor
498 lb Libbraille
500 lt LogText
502 mb MultiBraille
504 md MDV
506 mm BrailleMemo
508 mn MiniBraille
510 mp Mikropuhe
512 mt Metec
514 no no driver
516 np NinePoint
518 pg Pegasus
520 pm Papenmeier
522 sd SpeechDispatcher
524 sk Seika
526 sw Swift
528 th Theta
530 tn TechniBraille Systems Inc.
532 ts Telesensory Systems Inc.
534 tt TTY
536 vd VideoBraille
538 vo Voyager, Part232 (serial adapter), BraillePen/EasyLink
540 vr Virtual
542 vs VisioBraille
544 vv ViaVoice
546 xs ExternalSpeech
548 xw XWindow
550 A comma-delimited list of drivers may be specified. If this is
552 done then autodetection is performed using each listed driver in
553 sequence. You may need to experiment in order to determine the
554 most reliable order since some drivers autodetect better than
555 others.
556 If the single word auto is specified then autodetection is per‐
558 formed using only those drivers which are known to be reliable
559 for this purpose.
560
562 For full documentation, see brltty's on-line manual at
563 [http://brltty.com/documentation.html].
564brltty 5.5 2018-02-01 BRLTTY(1)