1BRLTTY(1)                    BRLTTY User's Manual                    BRLTTY(1)
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3
4

NAME

6       brltty - refreshable braille display driver for Linux/Unix
7

SYNOPSIS

9       brltty [option ...]
10

DESCRIPTION

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

OPTIONS

19       Options  can  be  passed  to  brltty in a number of ways.  From most to
20       least influential, these are:
21
22       1.  Command Line Options
23
24       2.  Boot Parameters
25
26       3.  Environment Variables (if the -E  (--environment-variables)  option
27           is in effect)
28
29       4.  The Configuration File
30
31       5.  Built-in Defaults
32
33   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
38       The following options are supported:
39
40       -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
45       -b driver,...|auto (--braille-driver=)
46              The  driver  for the braille display (see Driver Specification).
47              The built-in default is auto.
48
49       -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
53       -d device,... (--braille-device=)
54              The  device  to  which  the  braille  display is connected.  The
55              built-in default is usb:,bluetooth:.
56
57              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
62              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
67              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
75              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
86              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
92       -e (--standard-error)
93              Write logs to standard error rather than to the system log (use‐
94              ful for debugging).
95
96       -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
101       -h (--help)
102              Print a command line usage summary (commonly used options only),
103              and then exit.
104
105       -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
113       -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
117       -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
122              0   emergency
123
124              1   alert
125
126              2   critical
127
128              3   error
129
130              4   warning
131
132              5   notice
133
134              6   information
135
136              7   debug
137
138       The built-in default is notice.
139
140       -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
147              Linux/ALSA  the first available MIDI output port
148
149              Linux/OSS   /dev/sequencer
150
151       -n (--no-daemon)
152              Remain in the foreground (useful for debugging).
153
154       -o name=value,... (--override-preference=)
155              Explicit preference settings.
156
157       -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
162              FreeBSD     /dev/dsp
163
164              Linux/ALSA  hw:0,0
165
166              Linux/OSS   /dev/dsp
167
168              NetBSD      /dev/audio
169
170              OpenBSD     /dev/audio
171
172              Qnx         the preferred PCM output device
173
174              Solaris     /dev/audio
175
176       -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
182       -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
186       -s driver,...|auto (--speech-driver=)
187              The driver for the speech  synthesizer  (see  Driver  Specifica‐
188              tion).  The built-in default is auto.
189
190       -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
196       -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
208       -x driver (--screen-driver=)
209              The  screen  driver.   The  built-in default is operating system
210              appropriate.
211
212       -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
217       -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
225       -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
229       -E (--environment-variables)
230              Recognize environment variables.
231
232       -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
236       -H (--full-help)
237              Print a command line usage summary (all options), and then exit.
238
239       -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
244       -K arg (--keyboard-properties=)
245              Properties of the keyboard.
246
247       -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
252       -M csecs (--message-delay=)
253              The  message  hold time in hundredths of a second.  The built-in
254              default is 400 (4 seconds).
255
256       -N (--no-api)
257              Don't start the application programming interface.
258
259       -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
265       -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
270       -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
278       -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
283       -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
287       -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
294       -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
298       -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
303       -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
308       -Z text (--stop-message=)
309              The text to be shown when the braille driver stops.  The  built-
310              in default is BRLTTY stopped.
311
312   Environment Variables
313       The  following  environment variables are recognized if the -E (--envi‐
314       ronment-variables) option is specified:
315
316       BRLTTY_API_PARAMETERS=name=value,...
317              Parameters for the application programming interface.   See  the
318              -A (--api-parameters=) option for details.
319
320       BRLTTY_ATTRIBUTES_TABLE=table
321              The  attributes  table.  See the -a (--attributes-table=) option
322              for details.
323
324       BRLTTY_BRAILLE_DEVICE=device,...
325              The device to which the braille display is connected.   See  the
326              -d (--braille-device=) option for details.
327
328       BRLTTY_BRAILLE_DRIVER=driver,...|auto
329              The    driver   for   the   braille   display.    See   the   -b
330              (--braille-driver=) option for details.
331
332       BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
333              Parameters  for  the  braille  display  driver.   See   the   -B
334              (--braille-parameters=) option for details.
335
336       BRLTTY_CONFIGURATION_FILE=file
337              The  configuration  file.   See  the  -f (--configuration-file=)
338              option for details.
339
340       BRLTTY_CONTRACTION_TABLE=table
341              The contraction table.  See the -c (--contraction-table=) option
342              for details.
343
344       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
348       BRLTTY_PCM_DEVICE=device
349              The device to use for digital audio.  See the -p (--pcm-device=)
350              option for details.
351
352       BRLTTY_PREFERENCES_FILE=file
353              The  preferences  file.  See the -F (--preferences-file=) option
354              for details.
355
356       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
361       BRLTTY_SCREEN_DRIVER=driver
362              The screen driver.  See the  -x  (--screen-driver=)  option  for
363              details.
364
365       BRLTTY_SCREEN_PARAMETERS=name=value,...
366              Parameters  for the screen driver.  See the -X (--screen-parame‐
367              ters=) option for details.
368
369       BRLTTY_SPEECH_DRIVER=driver,...|auto
370              The  driver  for   the   speech   synthesizer.    See   the   -s
371              (--speech-driver=) option for details.
372
373       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
378       BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
379              Parameters  for  the  speech  synthesizer  driver.   See  the -S
380              (--speech-parameters=) option for details.
381
382       BRLTTY_TEXT_TABLE=table
383              The text table.  See the -t (--text-table=) option for details.
384
385   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
390       The following configuration directives are supported:
391
392       api-parameters name=value,...
393              Parameters for the application programming interface.   See  the
394              -A (--api-parameters=) option for details.
395
396       attributes-table table
397              The  attributes  table.  See the -a (--attributes-table=) option
398              for details.
399
400       braille-device device,...
401              The device to which the braille display is connected.   See  the
402              -d (--braille-device=) option for details.
403
404       braille-driver driver,...|auto
405              The    driver   for   the   braille   display.    See   the   -b
406              (--braille-driver=) option for details.
407
408       braille-parameters [driver:]name=value,...
409              Parameters  for  the  braille  display  driver.   See   the   -B
410              (--braille-parameters=) option for details.
411
412       contraction-table table
413              The contraction table.  See the -c (--contraction-table=) option
414              for details.
415
416       midi-device device
417              The device to use for the Musical Instrument Digital  Interface.
418              See the -m (--midi-device=) option for details.
419
420       pcm-device device
421              The device to use for digital audio.  See the -p (--pcm-device=)
422              option for details.
423
424       preferences-file file
425              The preferences file.  See the -F  (--preferences-file=)  option
426              for details.
427
428       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
433       screen-driver driver
434              The  screen  driver.   See  the -x (--screen-driver=) option for
435              details.
436
437       screen-parameters name=value,...
438              Parameters for the screen driver.  See the -X  (--screen-parame‐
439              ters=) option for details.
440
441       speech-driver driver,...|auto
442              The   driver   for   the   speech   synthesizer.    See  the  -s
443              (--speech-driver=) option for details.
444
445       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
450       speech-parameters [driver:]name=value,...
451              Parameters for  the  speech  synthesizer  driver.   See  the  -S
452              (--speech-parameters=) option for details.
453
454       text-table table
455              The text table.  See the -t (--text-table=) option for details.
456
457   Driver Specification
458       A  braille  display  or speech synthesizer driver must be specified via
459       its identification code:
460
461              al  Alva
462
463              an  Android
464
465              at  Albatross
466
467              ba  BrlAPI
468
469              bc  BrailComm
470
471              bd  Braudi
472
473              bg  B2G
474
475              bl  BrailleLite
476
477              bm  Baum
478
479              bn  BrailleNote
480
481              cb  CombiBraille
482
483              ce  Cebra
484
485              cn  Canute
486
487              ec  EcoBraille
488
489              en  eSpeak-NG
490
491              es  eSpeak
492
493              eu  EuroBraille
494
495              fl  FestivalLite
496
497              fs  FreedomScientific
498
499              fv  Festival
500
501              gs  GenericSay
502
503              hd  Hedo
504
505              hm  HIMS
506
507              ht  HandyTech
508
509              hw  HumanWare
510
511              ir  Iris
512
513              ic  Inceptor
514
515              lb  Libbraille
516
517              lt  LogText
518
519              mb  MultiBraille
520
521              md  MDV
522
523              mm  BrailleMemo
524
525              mn  MiniBraille
526
527              mp  Mikropuhe
528
529              mt  Metec
530
531              no  no driver
532
533              np  NinePoint
534
535              pg  Pegasus
536
537              pm  Papenmeier
538
539              sd  SpeechDispatcher
540
541              sk  Seika
542
543              sw  Swift
544
545              th  Theta
546
547              tn  TechniBraille Systems Inc.
548
549              ts  Telesensory Systems Inc.
550
551              tt  TTY
552
553              vd  VideoBraille
554
555              vo  Voyager, Part232 (serial adapter), BraillePen/EasyLink
556
557              vr  Virtual
558
559              vs  VisioBraille
560
561              vv  ViaVoice
562
563              xs  ExternalSpeech
564
565              xw  XWindow
566
567              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
573              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

SEE ALSO

578       For   full   documentation,   see   brltty's    on-line    manual    at
579       [http://brltty.app/documentation.html].
580
581
582
583brltty 6.1                        2020-04-06                         BRLTTY(1)
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