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 table. Relative paths are anchored
42 at /etc/brltty. The .atb extension is optional. The built-in
43 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:
73 serial:/dev/ttyS0, serial:ttyS0, /dev/ttyS0, 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 and then exit.
103 -i name (--speech-input=)
105 The file system object (FIFO, named pipe, named socket, etc)
106 which gives other applications access to brltty's speech driver
107 for text-to-speech conversion. It's created at start-up and
108 removed at termination. Relative paths are anchored at the cur‐
109 rent working directory. The built-in default is that the file
110 system object is not created.
111 -k file (--key-table=)
113 Path to key table file.
114 -l level (--log-level=)
116 The minimum severity level for messages written to the log. Any
117 of the following numbers, or any abbreviation of their corre‐
118 sponding names, may be specified:
119 0 emergency
121 1 alert
123 2 critical
125 3 error
127 4 warning
129 5 notice
131 6 information
133 7 debug
135 The built-in default is notice.
137 -m device (--midi-device=)
139 The device to use for the Musical Instrument Digital Interface.
140 For ALSA it's client:port, where each may be either a number or
141 a case-sensitive substring of its name. For other interfaces
142 it's the full path to an appropriate system device. The built-
143 in default is:
144 Linux/ALSA the first available MIDI output port
146 Linux/OSS /dev/sequencer
148 -n (--no-daemon)
150 Remain in the foreground (useful for debugging).
151 -p device (--pcm-device=)
153 The device to use for digital audio. For ALSA it's name[:argu‐
154 ment,...]. For other interfaces it's the full path to an appro‐
155 priate system device. The built-in default is:
156 FreeBSD /dev/dsp
158 Linux/ALSA hw:0,0
160 Linux/OSS /dev/dsp
162 NetBSD /dev/audio
164 OpenBSD /dev/audio
166 Qnx the preferred PCM output device
168 Solaris /dev/audio
170 -q (--quiet)
172 Suppress the start-up messages. This is done by reducing the
173 default log level (see the -l (--log-level=) option) to warning
174 (information if either -v (--verify) or -V (--version) is also
175 specified).
176 -r (--release-device)
178 Release the device to which the braille display is connected
179 when the current screen or window can't be read.
180 -s driver,...|auto (--speech-driver=)
182 The driver for the speech synthesizer (see Driver Specifica‐
183 tion). The built-in default is auto.
184 -t table (--text-table=)
186 The path to the text table. Relative paths are anchored at
187 /etc/brltty. The .ttb extension is optional. The built-in
188 default is nabcc.ttb (the North American Braille Computer Code).
189 -v (--verify)
191 Print the start-up messages and then exit. This always includes
192 the versions of brltty itself, the server side of its applica‐
193 tion programming interface, and each of the selected braille and
194 speech drivers. If the -q (--quiet) option isn't also specified
195 then it also includes the values of the options after all
196 sources have been considered. If more than one braille driver
197 and/or more than one braille device has been specified then
198 braille display autodetection is performed. If more than one
199 speech driver has been specified then speech synthesizer autode‐
200 tection is performed.
201 -x driver (--screen-driver=)
203 The screen driver. The built-in default is operating system
204 appropriate.
205 -A name=value,... (--api-parameters=)
207 Parameters for the application programming interface. If the
208 same parameter is specified more than once then the rightmost
209 specification is used. Parameter names may be abbreviated.
210 -B [driver:]name=value,... (--braille-parameters=)
212 Parameters for the braille display driver. If the same parame‐
213 ter is specified more than once then the rightmost specification
214 is used. Parameter names may be abbreviated. If a parameter
215 assignment is qualified with a driver identification code then
216 it's only processed if that braille display driver is being
217 used.
218 -D (--drivers-directory=)
220 Path to directory for loading drivers.
221 -E (--environment-variables)
223 Recognize environment variables.
224 -F file (--preferences-file=)
226 The path to the preferences file. Relative paths are anchored
227 at /var/lib/brltty. The built-in default is brltty.prefs.
228 -H (--full-help)
230 Print a usage summary (all options), and then exit.
231 -I (--install-service)
233 (Windows only) Install brltty as the BrlAPI service so that it
234 will be automatically started when the system is booted and so
235 that applications can know that a BrlAPI server is running.
236 -K arg (--keyboard-properties=)
238 Properties of the keyboard.
239 -L file (--log-file=)
241 The file to which log messages are written. Relative paths are
242 anchored at the current working directory. The default is to
243 send log messages to the system log.
244 -M csecs (--message-delay=)
246 The message hold time in hundredths of a second. The built-in
247 default is 400 (4 seconds).
248 -N (--no-api)
250 Don't start the application programming interface.
251 -P file (--pid-file=)
253 The full path to the process identifier file. If this option is
254 supplied, brltty writes its process identifier (pid) into the
255 specified file at start-up. The file is removed when brltty
256 terminates.
257 -R (--remove-service)
259 (Windows only) Remove the BrlAPI service so that brltty will not
260 be automatically started when the system is booted and so that
261 applications can know that no BrlAPI server is running.
262 -S [driver:]name=value,... (--speech-parameters=)
264 Parameters for the speech synthesizer driver. If the same
265 parameter is specified more than once then the rightmost speci‐
266 fication is used. Parameter names may be abbreviated. If a
267 parameter assignment is qualified with a driver identification
268 code then it's only processed if that speech synthesizer driver
269 is being used.
270 -T directory (--tables-directory=)
272 Path to directory for text and attributes tables.
273 -U csecs (--update-interval=)
275 The braille window update interval in hundredths of a second.
276 The built-in default is 4 (25 times per second).
277 -V (--version)
279 Print the versions of brltty itself, the server side of its
280 application programming interface, and those drivers which were
281 configured in at build-time, and then exit. If the -q (--quiet)
282 option isn't also specified then also print copyright informa‐
283 tion.
284 -W directory (--writable-directory=)
286 Path to directory which can be written to.
287 -X name=value,... (--screen-parameters=)
289 Parameters for the screen driver. If the same parameter is
290 specified more than once then the rightmost specification is
291 used. Parameter names may be abbreviated.
292 Environment Variables
294 The following environment variables are recognized if the -E (--envi‐
295 ronment-variables) option is specified:
296 BRLTTY_API_PARAMETERS=name=value,...
298 Parameters for the application programming interface. See the
299 -A (--api-parameters=) option for details.
300 BRLTTY_ATTRIBUTES_TABLE=table
302 The attributes table. See the -a (--attributes-table=) option
303 for details.
304 BRLTTY_BRAILLE_DEVICE=device,...
306 The device to which the braille display is connected. See the
307 -d (--braille-device=) option for details.
308 BRLTTY_BRAILLE_DRIVER=driver,...|auto
310 The driver for the braille display. See the -b
311 (--braille-driver=) option for details.
312 BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
314 Parameters for the braille display driver. See the -B
315 (--braille-parameters=) option for details.
316 BRLTTY_CONFIGURATION_FILE=file
318 The configuration file. See the -f (--configuration-file=)
319 option for details.
320 BRLTTY_CONTRACTION_TABLE=table
322 The contraction table. See the -c (--contraction-table=) option
323 for details.
324 BRLTTY_MIDI_DEVICE=device
326 The device to use for the Musical Instrument Digital Interface.
327 See the -m (--midi-device=) option for details.
328 BRLTTY_PCM_DEVICE=device
330 The device to use for digital audio. See the -p (--pcm-device=)
331 option for details.
332 BRLTTY_PREFERENCES_FILE=file
334 The preferences file. See the -F (--preferences-file=) option
335 for details.
336 BRLTTY_RELEASE_DEVICE=on|off
338 Release the device to which the braille display is connected
339 when the current screen or window can't be read. See the -r
340 (--release-device) option for details.
341 BRLTTY_SCREEN_DRIVER=driver
343 The screen driver. See the -x (--screen-driver=) option for
344 details.
345 BRLTTY_SCREEN_PARAMETERS=name=value,...
347 Parameters for the screen driver. See the -X (--screen-parame‐
348 ters=) option for details.
349 BRLTTY_SPEECH_DRIVER=driver,...|auto
351 The driver for the speech synthesizer. See the -s
352 (--speech-driver=) option for details.
353 BRLTTY_SPEECH_INPUT=name
355 The file system object which gives other applications access to
356 brltty's speech driver for text-to-speech conversion. See the
357 -i (--speech-input=) option for details.
358 BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
360 Parameters for the speech synthesizer driver. See the -S
361 (--speech-parameters=) option for details.
362 BRLTTY_TEXT_TABLE=table
364 The text table. See the -t (--text-table=) option for details.
365 The Configuration File
367 Blank lines are ignored. If the character # occurs on any line then
368 all characters from it to the end of that line are treated as a com‐
369 ment.
370 The following configuration directives are supported:
372 api-parameters name=value,...
374 Parameters for the application programming interface. See the
375 -A (--api-parameters=) option for details.
376 attributes-table table
378 The attributes table. See the -a (--attributes-table=) option
379 for details.
380 braille-device device,...
382 The device to which the braille display is connected. See the
383 -d (--braille-device=) option for details.
384 braille-driver driver,...|auto
386 The driver for the braille display. See the -b
387 (--braille-driver=) option for details.
388 braille-parameters [driver:]name=value,...
390 Parameters for the braille display driver. See the -B
391 (--braille-parameters=) option for details.
392 contraction-table table
394 The contraction table. See the -c (--contraction-table=) option
395 for details.
396 midi-device device
398 The device to use for the Musical Instrument Digital Interface.
399 See the -m (--midi-device=) option for details.
400 pcm-device device
402 The device to use for digital audio. See the -p (--pcm-device=)
403 option for details.
404 The preferences file.
406 See the -F (--preferences-file=) option for details.
407 release-device on|off
409 Release the device to which the braille display is connected
410 when the current screen or window can't be read. See the -r
411 (--release-device) option for details.
412 screen-driver driver
414 The screen driver. See the -x (--screen-driver=) option for
415 details.
416 screen-parameters name=value,...
418 Parameters for the screen driver. See the -X (--screen-parame‐
419 ters=) option for details.
420 speech-driver driver,...|auto
422 The driver for the speech synthesizer. See the -s
423 (--speech-driver=) option for details.
424 speech-input 0me
426 The file system object which gives other applications access to
427 brltty's speech driver for text-to-speech conversion. See the
428 -i (--speech-input=) option for details.
429 speech-parameters [driver:]name=value,...
431 Parameters for the speech synthesizer driver. See the -S
432 (--speech-parameters=) option for details.
433 text-table table
435 The text table. See the -t (--text-table=) option for details.
436 Driver Specification
438 A braille display or speech synthesizer driver must be specified via
439 its identification code:
440 al Alva
442 at Albatross
444 ba BrlAPI
446 bc BrailComm
448 bd Braudi
450 bl BrailleLite
452 bm Baum
454 bn BrailleNote
456 cb CombiBraille
458 ec EcoBraille
460 es eSpeak
462 eu EuroBraille
464 fl FestivalLite
466 fs FreedomScientific
468 fv Festival
470 gs GenericSay
472 hm HIMS
474 ht HandyTech
476 hw HumanWare
478 ir Iris
480 lb Libbraille
482 lt LogText
484 mb MultiBraille
486 md MDV
488 mn MiniBraille
490 mp Mikropuhe
492 mt Metec
494 no no driver
496 np NinePoint
498 pg Pegasus
500 pm Papenmeier
502 sd SpeechDispatcher
504 sk Seika
506 sw Swift
508 th Theta
510 tn TechniBraille Systems Inc.
512 ts Telesensory Systems Inc.
514 tt TTY
516 vd VideoBraille
518 vo Voyager, Part232 (serial adapter), BraillePen/EasyLink
520 vr Virtual
522 vs VisioBraille
524 vv ViaVoice
526 xs ExternalSpeech
528 xw XWindow
530 A comma-delimited list of drivers may be specified. If this is
532 done then autodetection is performed using each listed driver in
533 sequence. You may need to experiment in order to determine the
534 most reliable order since some drivers autodetect better than
535 others.
536 If the single word auto is specified then autodetection is per‐
538 formed using only those drivers which are known to be reliable
539 for this purpose.
540
542 For full documentation, see brltty's on-line manual at
543 [http://mielke.cc/brltty/doc/Manual-HTML/Manual.html].
544brltty 4.5 Apr 2013 BRLTTY(1)