brltty

BRLTTY(1)                     The BRLTTY Project                     BRLTTY(1)



NAME
       brltty - refreshable braille display driver for Linux/Unix

SYNOPSIS
       brltty [option ...]

DESCRIPTION
       brltty  is  a  background process (daemon) which provides access to the
       console screen (when in text mode) for a blind person using a  refresh‐
       able braille display.  It drives the braille display, and provides com‐
       plete screen review functionality.  Some  speech  capability  has  also
       been incorporated.

OPTIONS
       Options  can  be  passed  to  brltty in a number of ways.  From most to
       least influential, these are:

       1.  Command Line Options

       2.  Boot Parameters

       3.  Environment Variables (if the -E  (--environment-variables)  option
           is in effect)

       4.  The Configuration File

       5.  Built-in Defaults

   Command Line Options
       The  options  are  processed  sequentially  from  left to right.  If an
       option is specified more than once, or  in  case  of  a  conflict,  the
       rightmost specification takes precedence.

       The following options are supported:

       -a table (--attributes-table=)
              The  path  to  the attributes translation table.  Relative paths
              are anchored at /etc/brltty/.  The .atb extension  is  optional.
              The built-in default is attributes.atb.

       -b driver,...|auto (--braille-driver=)
              The  driver  for the braille display (see Driver Specification).
              The built-in default is auto.

       -c table (--contraction-table=)
              The path to the contraction table.  Relative paths are  anchored
              at /etc/brltty/.  The .ctb extension is optional.

       -d device,... (--braille-device=)
              The  device  to  which  the  braille  display is connected.  The
              built-in default is usb:.

              The general form of a braille  device  specification  is  quali‐
              fier:data.  For backward compatibility with earlier releases, if
              the qualifier is omitted then serial: is assumed.  The following
              device types are supported:

              Bluetooth
                     For  a  bluetooth  device,  specify  bluez:address.   The
                     address must be six two-digit hexadecimal  numbers  sepa‐
                     rated by colons, e.g.  01:23:45:67:89:AB.

              Serial For a serial device, specify serial:/path/to/device.  The
                     serial: qualifier is optional (for  backward  compatibil‐
                     ity).   If a relative path is given then it's anchored at
                     /dev/ (the usual location where devices are defined on  a
                     Unix-like  system).   The following device specifications
                     all refer to the  primary  serial  device:  serial:/dev/,
                     serial:, /dev/, .

              USB    For  a  USB device, specify usb:.  brltty will search for
                     the first USB device which matches  the  braille  display
                     driver  being  used.   If this is inadequate, e.g. if you
                     have more than one USB braille display which requires the
                     same driver, then you can refine the device specification
                     by appending the serial number of the display to it, e.g.
                     usb:12345.   N.B.:  The "identification by serial number"
                     feature doesn't work for some models because  some  manu‐
                     facturers either don't set the USB serial number descrip‐
                     tor at all or do set it but not to a unique value.

              A comma-delimited list of braille devices may be specified.   If
              this  is  done  then  autodetection  is performed on each listed
              device in sequence.  This feature is particularly useful if  you
              have  a braille display with more than one interrface, e.g. both
              a serial and a USB port.

       -e (--standard-error)
              Write logs to standard error rather than to the system log (use‐
              ful for debugging).

       -f file (--configuration-file=)
              The path to the configuration file.  Relative paths are anchored
              at the current  working  directory.   The  built-in  default  is
              /etc/brltty.conf.

       -h (--help)
              Print a command line usage summary and then exit.

       -l level (--log-level=)
              The minimum severity level for messages written to the log.  Any
              of the following numbers, or any abbreviation  of  their  corre‐
              sponding names, may be specified:

              0   emergency

              1   alert

              2   critical

              3   error

              4   warning

              5   notice

              6   information

              7   debug

       The built-in default is notice.

       -m device (--midi-device=)
              The  device to use for the Musical Instrument Digital Interface.
              For ALSA it's client:port, where each may be either a number  or
              a  case-sensitive  substring  of its name.  For other interfaces
              it's the full path to an appropriate system device.  The  built-
              in default is:

              Linux/ALSA  the first available MIDI output port

              Linux/OSS   /dev/sequencer

       -n (--no-daemon)
              Remain in the foreground (useful for debugging).

       -p device (--pcm-device=)
              The  device to use for digital audio.  For ALSA it's name[:argu‐
              ment,...].  For other interfaces it's the full path to an appro‐
              priate system device.  The built-in default is:

              FreeBSD     /dev/dsp

              Linux/ALSA  hw:0,0

              Linux/OSS   /dev/dsp

              NetBSD      /dev/audio

              OpenBSD     /dev/audio

              Qnx         the preferred PCM output device

              Solaris     /dev/audio

       -q (--quiet)
              Suppress  the  start-up  messages.  This is done by reducing the
              default log level (see the -l (--log-level=) option) to  warning
              (information  if  either -v (--verify) or -V (--version) is also
              specified).

       -r (--release-device)
              Release the device to which the  braille  display  is  connected
              when the current screen or window can't be read.

       -s driver,...|auto (--speech-driver=)
              The  driver  for  the  speech synthesizer (see Driver Specifica‐
              tion).  The built-in default is auto.

       -t table (--text-table=)
              The path to the text  translation  table.   Relative  paths  are
              anchored  at /etc/brltty/.  The .ttb extension is optional.  The
              built-in default is nabcc.ttb (the North American  Braille  Com‐
              puter Code).

       -v (--verify)
              Print the start-up messages and then exit.  This always includes
              the versions of brltty itself, the server side of  its  applica‐
              tion programming interface, and each of the selected braille and
              speech drivers.  If the -q (--quiet) option isn't also specified
              then  it  also  includes  the  values  of  the options after all
              sources have been considered.  If more than one  braille  driver
              and/or  more  than  one  braille  device has been specified then
              braille display autodetection is performed.  If  more  than  one
              speech driver has been specified then speech synthesizer autode‐
              tection is performed.

       -x driver (--screen-driver=)
              The screen driver.  The built-in  default  is  operating  system
              appropriate.

       -A name=value,... (--api-parameters=)
              Parameters  for  the  application programming interface.  If the
              same parameter is specified more than once  then  the  rightmost
              specification is used.  Parameter names may be abbreviated.

       -B [driver:]name=value,... (--braille-parameters=)
              Parameters  for the braille display driver.  If the same parame‐
              ter is specified more than once then the rightmost specification
              is  used.   Parameter  names may be abbreviated.  If a parameter
              assignment is qualified with a driver identification  code  then
              it's  only  processed  if  that  braille display driver is being
              used.

       -E (--environment-variables)
              Recognize environment variables.

       -F fifo (--speech-fifo=)
              The FIFO which  gives  other  applications  access  to  brltty's
              speech driver.  It's created at start-up and removed at termina‐
              tion.  Relative paths are anchored at /etc/brltty/.  The  built-
              in default is that no FIFO is created.

       -I (--install-service)
              (Windows  only)  Install brltty as the BrlAPI service so that it
              will be automatically started when the system is booted  and  so
              that applications can know that a BrlAPI server is running.

       -M csecs (--message-delay=)
              The  message  hold time in hundredths of a second.  The built-in
              default is 400 (4 seconds).

       -N (--no-api)
              Don't start the application programming interface.

       -P file (--pid-file=)
              The full path to the process identifier file.  If this option is
              supplied,  brltty  writes  its process identifier (pid) into the
              specified file at start-up.  The file  is  removed  when  brltty
              terminates.

       -R (--remove-service)
              (Windows only) Remove the BrlAPI service so that brltty will not
              be automatically started when the system is booted and  so  that
              applications can know that no BrlAPI server is running.

       -S [driver:]name=value,... (--speech-parameters=)
              Parameters  for  the  speech  synthesizer  driver.   If the same
              parameter is specified more than once then the rightmost  speci‐
              fication  is  used.   Parameter  names may be abbreviated.  If a
              parameter assignment is qualified with a  driver  identification
              code  then it's only processed if that speech synthesizer driver
              is being used.

       -U csecs (--update-interval=)
              The braille window update interval in hundredths  of  a  second.
              The built-in default is 4 (25 times per second).

       -V (--version)
              Print  the  versions  of  brltty  itself, the server side of its
              application programming interface, and those drivers which  were
              configured in at build-time, and then exit.  If the -q (--quiet)
              option isn't also specified then also print  copyright  informa‐
              tion.

       -X name=value,... (--screen-parameters=)
              Parameters  for  the  screen  driver.   If the same parameter is
              specified more than once then  the  rightmost  specification  is
              used.  Parameter names may be abbreviated.

   Environment Variables
       The  following  environment variables are recognized if the -E (--envi‐
       ronment-variables) option is specified:

       BRLTTY_API_PARAMETERS=name=value,...
              Parameters for the application programming interface.   See  the
              -A (--api-parameters=) option for details.

       BRLTTY_ATTRIBUTES_TABLE=table
              The  attributes translation table.  See the -a (--attributes-ta‐
              ble=) option for details.

       BRLTTY_BRAILLE_DEVICE=device,...
              The device to which the braille display is connected.   See  the
              -d (--braille-device=) option for details.

       BRLTTY_BRAILLE_DRIVER=driver,...|auto
              The  driver  for  the  braille  display.  See the -b (--braille-
              driver=) option for details.

       BRLTTY_BRAILLE_PARAMETERS=[driver:]name=value,...
              Parameters  for  the  braille  display  driver.   See   the   -B
              (--braille-parameters=) option for details.

       BRLTTY_CONFIGURATION_FILE=file
              The  configuration  file.   See  the  -f (--configuration-file=)
              option for details.

       BRLTTY_CONTRACTION_TABLE=table
              The contraction table.  See the -c (--contraction-table=) option
              for details.

       BRLTTY_MIDI_DEVICE=device
              The  device to use for the Musical Instrument Digital Interface.
              See the -m (--midi-device=) option for details.

       BRLTTY_PCM_DEVICE=device
              The device to use for digital audio.  See the -p (--pcm-device=)
              option for details.

       BRLTTY_RELEASE_DEVICE=on|off
              Release  the  device  to  which the braille display is connected
              when the current screen or window can't be  read.   See  the  -r
              (--release-device) option for details.

       BRLTTY_SCREEN_DRIVER=driver
              The  screen  driver.   See  the -x (--screen-driver=) option for
              details.

       BRLTTY_SCREEN_PARAMETERS=name=value,...
              Parameters for the screen driver.  See the -X  (--screen-parame‐
              ters=) option for details.

       BRLTTY_SPEECH_DRIVER=driver,...|auto
              The  driver  for  the speech synthesizer.  See the -s (--speech-
              driver=) option for details.

       BRLTTY_SPEECH_FIFO=fifo
              The FIFO which  gives  other  applications  access  to  brltty's
              speech driver.  See the -F (--speech-fifo=) option for details.

       BRLTTY_SPEECH_PARAMETERS=[driver:]name=value,...
              Parameters  for  the  speech  synthesizer  driver.   See  the -S
              (--speech-parameters=) option for details.

       BRLTTY_TEXT_TABLE=table
              The text translation table.  See the -t  (--text-table=)  option
              for details.

   The Configuration File
       Blank  lines  are  ignored.  If the character # occurs on any line then
       all characters from it to the end of that line are treated  as  a  com‐
       ment.

       The following configuration directives are supported:

       api-parameters name=value,...
              Parameters  for  the application programming interface.  See the
              -A (--api-parameters=) option for details.

       attributes-table table
              The attributes translation table.  See the -a  (--attributes-ta‐
              ble=) option for details.

       braille-device device,...
              The  device  to which the braille display is connected.  See the
              -d (--braille-device=) option for details.

       braille-driver driver,...|auto
              The driver for the braille  display.   See  the  -b  (--braille-
              driver=) option for details.

       braille-parameters [driver:]name=value,...
              Parameters   for   the  braille  display  driver.   See  the  -B
              (--braille-parameters=) option for details.

       contraction-table table
              The contraction table.  See the -c (--contraction-table=) option
              for details.

       midi-device device
              The  device to use for the Musical Instrument Digital Interface.
              See the -m (--midi-device=) option for details.

       pcm-device device
              The device to use for digital audio.  See the -p (--pcm-device=)
              option for details.

       release-device on|off
              Release  the  device  to  which the braille display is connected
              when the current screen or window can't be  read.   See  the  -r
              (--release-device) option for details.

       screen-driver driver
              The  screen  driver.   See  the -x (--screen-driver=) option for
              details.

       screen-parameters name=value,...
              Parameters for the screen driver.  See the -X  (--screen-parame‐
              ters=) option for details.

       speech-driver driver,...|auto
              The  driver  for  the speech synthesizer.  See the -s (--speech-
              driver=) option for details.

       speech-fifo fifo
              The FIFO which  gives  other  applications  access  to  brltty's
              speech driver.  See the -F (--speech-fifo=) option for details.

       speech-parameters [driver:]name=value,...
              Parameters  for  the  speech  synthesizer  driver.   See  the -S
              (--speech-parameters=) option for details.

       text-table table
              The text translation table.  See the -t  (--text-table=)  option
              for details.

   Driver Specification
       A  braille  display  or speech synthesizer driver must be specified via
       its identification code:

              al  Alva

              at  Albatross

              ba  BrlAPI

              bd  Braudi

              bl  BrailleLite

              bm  Baum

              bn  BrailleNote

              cb  CombiBraille

              ec  EcoBraille

              es  ExternalSpeech

              eu  EuroBraille

              fl  FestivalLite

              fs  FreedomScientific

              fv  Festival

              gs  GenericSay

              hm  HIMS

              ht  HandyTech

              il  IrisLinux

              lb  Libbraille

              lt  LogText

              mb  MultiBraille

              md  MDV

              mn  MiniBraille

              mp  Mikropuhe

              no  no driver

              pg  Pegasus

              pm  Papenmeier

              sd  SpeechDispatcher

              sk  Seika

              sw  Swift

              th  Theta

              tn  TechniBraille Systems Inc.

              ts  Telesensory Systems Inc.

              tt  TTY

              vd  VideoBraille

              vo  Voyager

              vr  Virtual

              vs  VisioBraille

              vv  ViaVoice

              xw  XWindow

              A comma-delimited list of drivers may be specified.  If this  is
              done then autodetection is performed using each listed driver in
              sequence.  You may need to experiment in order to determine  the
              most  reliable  order  since some drivers autodetect better than
              others.

              If the single word auto is specified then autodetection is  per‐
              formed  using  only those drivers which are known to be reliable
              for this purpose.

SEE ALSO
       For   full   documentation,   see   brltty's    on-line    manual    at
       [http://mielke.cc/brltty/doc/Manual-HTML/Manual.html].



brltty 4.1                       October 2009                        BRLTTY(1)