Documents/brltty.1.in - brltty - Git at Google

 .\" @configure_input@
 .\"
 .\" BRLTTY - A background process providing access to the console screen (when in
 .\"          text mode) for a blind person using a refreshable braille display.
 .\"
 .\" Copyright (C) 1995-2023 by The BRLTTY Developers.
 .\"
 .\" BRLTTY comes with ABSOLUTELY NO WARRANTY.
 .\"
 .\" This is free software, placed under the terms of the
 .\" GNU Lesser General Public License, as published by the Free Software
 .\" Foundation; either version 2.1 of the License, or (at your option) any
 .\" later version. Please see the file LICENSE-LGPL for details.
 .\"
 .\" Web Page: http://brltty.app/
 .\"
 .\" This software is maintained by Dave Mielke <dave@mielke.cc>.
 .\"
 .TH "BRLTTY" "1" "July 2023" "@PACKAGE_TARNAME@ @PACKAGE_VERSION@" "@PACKAGE_NAME@ User's Manual"
 .SH NAME
 brltty \- refreshable braille display driver for Linux/Unix
 .SH SYNOPSIS
 \fBbrltty \fR[\fIoption\fR ...]
 .SH DESCRIPTION
 .B brltty
 is a background process (daemon)
 which provides access to the console screen (when in text mode)
 for a blind person using a refreshable braille display.
 It drives the braille display,
 and provides complete screen review functionality.
 Some speech capability has also been incorporated.
 .SH OPTIONS
 Options can be passed to
 .B brltty
 in a number of ways.
 From most to least influential, these are:
 .IP 1. 4
 Command Line Options
 .IP 2. 4
 Boot Parameters
 .IP 3. 4
 Environment Variables
 (if the
 .B \-E
 .RB "(" "\-\-environment\-variables" ")"
 option is in effect)
 .IP 4. 4
 The Configuration File
 .IP 5. 4
 Built-in Defaults
 .SS "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.
 .PP
 The following options are supported:
 .TP
 \fB\-a \fItable\fR (\fB\-\-attributes\-table=\fR)
 The path to the attributes table.
 Relative paths are anchored at
 .BR "@TABLES_DIRECTORY@/@ATTRIBUTES_TABLES_SUBDIRECTORY@" "."
 The
 .B ".atb"
 extension is optional.
 The built-in default is
 .BR "@attributes_table@.atb" "."
 .TP
 \fB\-b \fIdriver\fB,\fR...|\fBauto\fR (\fB\-\-braille\-driver=\fR)
 The driver for the braille display
 (see Driver Specification).
 The built-in default is \fBauto\fR.
 .TP
 \fB\-c \fItable\fR (\fB\-\-contraction\-table=\fR)
 The path to the contraction table.
 Relative paths are anchored at
 .BR "@TABLES_DIRECTORY@/@CONTRACTION_TABLES_SUBDIRECTORY@" "."
 The
 .B ".ctb"
 extension is optional.
 .TP
 \fB\-d \fIdevice\fB,\fR... (\fB\-\-braille\-device=\fR)
 The device to which the braille display is connected.
 The built-in default is \fB@braille_device@\fR.
 .RS
 .PP
 The general form of a braille device specification is
 \fIqualifier\fB:\fIdata\fR.
 For backward compatibility with earlier releases,
 if the qualifier is omitted then
 .B serial:
 is assumed.
 The following device types are supported:
 .TP
 .B Bluetooth
 For a bluetooth device, specify \fBbluetooth:\fIaddress\fR.
 The address must be six two-digit hexadecimal numbers separated by colons, e.g.
 .BR "01:23:45:67:89:AB" "."
 .TP
 .B Serial
 For a serial device, specify \fBserial:\fIdevice\fR.
 The
 .B serial:
 qualifier is optional (for backward compatibility).
 If a relative path is given then it's anchored at
 .B /dev/
 (the usual location where devices are defined on a Unix-like system).
 The following device specifications all refer
 to the primary serial device on Linux:
 .BR "serial:@serial_first_device@" ","
 .BR "serial:/dev/@serial_first_device@" ","
 .BR "@serial_first_device@" ","
 .BR "/dev/@serial_first_device@" "."
 .TP
 .B USB
 For a USB device, specify \fBusb:\fR.
 .B 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.
 .BR "usb:12345" "."
 N.B.:
 The "identification by serial number" feature doesn't work for some models
 because some manufacturers
 either don't set the USB serial number descriptor at all
 or do set it but not to a unique value.
 .PP
 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 interface,
 e.g. both a serial and a USB port.
 .RE
 .TP
 \fB\-e\fR (\fB\-\-standard\-error\fR)
 Write logs to standard error rather than to the system log (useful for debugging).
 .TP
 \fB\-f \fIfile\fR (\fB\-\-configuration\-file=\fR)
 The path to the configuration file.
 Relative paths are anchored at the current working directory.
 The built-in default is
 .BR "@CONFIGURATION_DIRECTORY@/@CONFIGURATION_FILE@" "."
 .TP
 \fB\-h\fR (\fB\-\-help\fR)
 Print a command line usage summary (commonly used options only),
 and then exit.
 .TP
 \fB\-i \fIname\fR (\fB\-\-speech\-input=\fR)
 The file system object
 (FIFO, named pipe, named socket, etc)
 which gives other applications access to
 .BR brltty 's
 speech driver for text-to-speech conversion.
 It's created at start-up and removed at termination.
 Relative paths are anchored at the current working directory.
 The built-in default is
 that the file system object is not created.
 .TP
 \fB\-k \fItable\fR (\fB\-\-keyboard\-table=\fR)
 The path to the keyboard table.
 Relative paths are anchored at
 .BR "@TABLES_DIRECTORY@/@KEYBOARD_TABLES_SUBDIRECTORY@" "."
 The
 .B ".ktb"
 extension is optional.
 .TP
 \fB\-l \fIlevel\fR (\fB\-\-log\-level=\fR)
 The minimum severity level for messages written to the log.
 Any of the following numbers,
 or any abbreviation of their corresponding names,
 may be specified:
 .RS
 .TP 4
 .B 0
 .B emergency
 .TP 4
 .B 1
 .B alert
 .TP 4
 .B 2
 .B critical
 .TP 4
 .B 3
 .B error
 .TP 4
 .B 4
 .B warning
 .TP 4
 .B 5
 .B notice
 .TP 4
 .B 6
 .B information
 .TP 4
 .B 7
 .B debug
 .RE
 .PP
 The built-in default is
 .BR "notice" "."
 .TP
 \fB\-m \fIdevice\fR (\fB\-\-midi\-device=\fR)
 The device to use for the Musical Instrument Digital Interface.
 For ALSA it's \fIclient\fB:\fIport\fR,
 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:
 .RS
 .IP Linux/ALSA 12
 the first available MIDI output port
 .IP Linux/OSS 12
 .B /dev/sequencer
 .RE
 .TP
 \fB\-n\fR (\fB\-\-no\-daemon\fR)
 Remain in the foreground (useful for debugging).
 .TP
 \fB\-o \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-override\-preference=\fR)
 Override a preference setting.
 For the location of the preferences file, see the
 .B \-F
 .RB "(" "\-\-preferences\-file" ")"
 option.
 .TP
 \fB\-p \fIdevice\fR (\fB\-\-pcm\-device=\fR)
 The device to use for digital audio.
 For ALSA it's \fIname\fR[\fB:\fIargument\fB,\fR...].
 For other interfaces it's the full path to an appropriate system device.
 The built-in default is:
 .RS
 .IP FreeBSD 12
 .B /dev/dsp
 .IP Linux/ALSA 12
 .B hw:0,0
 .IP Linux/OSS 12
 .B /dev/dsp
 .IP NetBSD 12
 .B /dev/audio
 .IP OpenBSD 12
 .B /dev/audio
 .IP Qnx 12
 the preferred PCM output device
 .IP Solaris 12
 .B /dev/audio
 .RE
 .TP
 \fB\-q\fR (\fB\-\-quiet\fR)
 Suppress the start-up messages.
 This is done by reducing the default log level
 (see the
 .B \-l
 .RB "(" "\-\-log\-level=" ")"
 option)
 to
 .B warning
 .RB "(" "information"
 if either
 .B \-v
 .RB "(" "\-\-verify" ")"
 or
 .B \-V
 .RB "(" "\-\-version" ")"
 is also specified).
 .TP
 \fB\-r\fR (\fB\-\-release\-device\fR)
 Release the device to which the braille display is connected
 when the current screen or window can't be read.
 .TP
 \fB\-s \fIdriver\fB,\fR...|\fBauto\fR (\fB\-\-speech\-driver=\fR)
 The driver for the speech synthesizer
 (see Driver Specification).
 The built-in default is \fBauto\fR.
 .TP
 \fB\-t \fItable\fR (\fB\-\-text\-table=\fR)
 The path to the text table.
 Relative paths are anchored at
 .BR "@TABLES_DIRECTORY@/@TEXT_TABLES_SUBDIRECTORY@" "."
 The
 .B ".ttb"
 extension is optional.
 The built-in default is
 .B "@text_table@.ttb"
 (the North American Braille Computer Code).
 .TP
 \fB\-v\fR (\fB\-\-verify\fR)
 Print the start-up messages and then exit.
 This always includes the versions of
 .B brltty
 itself,
 the server side of its application programming interface,
 and each of the selected braille and speech drivers.
 If the
 .B \-q
 .RB "(" "\-\-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 autodetection is performed.
 .TP
 \fB\-x \fIdriver\fR (\fB\-\-screen\-driver=\fR)
 The screen driver.
 The built-in default is operating system appropriate.
 .TP
 \fB\-A \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-api\-parameters=\fR)
 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.
 .TP
 \fB\-B \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR... (\fB\-\-braille\-parameters=\fR)
 Parameters for the braille display driver.
 If the same parameter 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.
 .TP
 \fB\-D \fIdirectory\fR (\fB\-\-drivers\-directory=\fR)
 The path to the directory which contains
 the dynamically loadable driver objects.
 The built-in default is
 .RB "@DRIVERS_DIRECTORY@" "."
 .TP
 \fB\-E\fR (\fB\-\-environment\-variables\fR)
 Recognize environment variables.
 .TP
 \fB\-F \fIfile\fR (\fB\-\-preferences\-file=\fR)
 The path to the preferences file.
 Relative paths are anchored at
 .BR "@UPDATABLE_DIRECTORY@" "."
 The built-in default is
 .BR "@PREFERENCES_FILE@" "."
 .TP
 \fB\-H\fR (\fB\-\-full\-help\fR)
 Print a command line usage summary (all options),
 and then exit.
 .TP
 \fB\-I\fR (\fB\-\-install\-service\fR)
 (Windows only)
 Install
 .B brltty
 as the
 .B BrlAPI
 service so that it will be automatically started when the system is booted,
 and so that applications can know that a
 .B BrlAPI
 server is running.
 .TP
 \fB\-K \fIarg\fR (\fB\-\-keyboard\-properties=\fR)
 Properties of the keyboard.
 .TP
 \fB\-L \fIfile\fR (\fB\-\-log\-file=\fR)
 The file to which log messages are written.
 Relative paths are anchored at the current working directory.
 The default is to send log messages to the system log.
 .TP
 \fB\-M \fIcsecs\fR (\fB\-\-message\-delay=\fR)
 The message hold time in hundredths of a second.
 The built-in default is
 .B 400
 (4 seconds).
 .TP
 \fB\-N\fR (\fB\-\-no\-api\fR)
 Don't start the application programming interface.
 .TP
 \fB\-P \fIfile\fR (\fB\-\-pid\-file=\fR)
 The full path to the process identifier file.
 If this option is supplied,
 .B brltty
 writes its process identifier (pid) into the specified file at start-up.
 The file is removed when
 .B brltty
 terminates.
 .TP
 \fB\-R\fR (\fB\-\-remove\-service\fR)
 (Windows only)
 Remove the
 .B BrlAPI
 service so that
 .B brltty
 will not be automatically started when the system is booted,
 and so that applications can know that no
 .B BrlAPI
 server is running.
 .TP
 \fB\-S \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR... (\fB\-\-speech\-parameters=\fR)
 Parameters for the speech synthesizer driver.
 If the same parameter 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 speech synthesizer driver is being used.
 .TP
 \fB\-T \fIdirectory\fR (\fB\-\-tables\-directory=\fR)
 The path to the directory which contains
 the text, contraction, attributes, keyboard, and input tables.
 The built-in default is
 .RB "@TABLES_DIRECTORY@" "."
 .TP
 \fB\-U \fIdirectory\fR (\fB\-\-updatable\-directory=\fR)
 The path to a directory which contains files that can be updated.
 The built-in default is
 .RB "@UPDATABLE_DIRECTORY@" "."
 .TP
 \fB\-V\fR (\fB\-\-version\fR)
 Print the versions of
 .B 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
 .B \-q
 .RB "(" "\-\-quiet" ")"
 option isn't also specified
 then also print copyright information.
 .TP
 \fB\-W \fIdirectory\fR (\fB\-\-writable\-directory=\fR)
 The path to a directory which can be written to.
 The built-in default is
 .RB "@WRITABLE_DIRECTORY@" "."
 .TP
 \fB\-X \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-screen\-parameters=\fR)
 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.
 .TP
 \fB\-Y \fItext\fR (\fB\-\-start\-message=\fR)
 The text to be shown when the braille driver starts
 and to be spoken when the speech driver starts.
 The built-in default is
 .RB "@PACKAGE_NAME@ @PACKAGE_VERSION@" "."
 .TP
 \fB\-Z \fItext\fR (\fB\-\-stop\-message=\fR)
 The text to be shown when the braille driver stops.
 The built-in default is
 .RB "@PACKAGE_NAME@ stopped" "."
 .SS "Environment Variables"
 The following environment variables are recognized if the
 .B \-E
 .RB "(" "\-\-environment\-variables" ")"
 option is specified:
 .TP
 \fBBRLTTY_API_PARAMETERS=\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the application programming interface.
 See the
 .B \-A
 .RB "(" "\-\-api\-parameters=" ")"
 option for details.
 .TP
 \fBBRLTTY_ATTRIBUTES_TABLE=\fItable\fR
 The attributes table.
 See the
 .B \-a
 .RB "(" "\-\-attributes\-table=" ")"
 option for details.
 .TP
 \fBBRLTTY_BRAILLE_DEVICE=\fIdevice\fB,\fR...
 The device to which the braille display is connected.
 See the
 .B \-d
 .RB "(" "\-\-braille\-device=" ")"
 option for details.
 .TP
 \fBBRLTTY_BRAILLE_DRIVER=\fIdriver\fB,\fR...|\fBauto\fR
 The driver for the braille display.
 See the
 .B \-b
 .RB "(" "\-\-braille\-driver=" ")"
 option for details.
 .TP
 \fBBRLTTY_BRAILLE_PARAMETERS=\fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the braille display driver.
 See the
 .B \-B
 .RB "(" "\-\-braille\-parameters=" ")"
 option for details.
 .TP
 \fBBRLTTY_CONFIGURATION_FILE=\fIfile\fR
 The configuration file.
 See the
 .B \-f
 .RB "(" "\-\-configuration\-file=" ")"
 option for details.
 .TP
 \fBBRLTTY_CONTRACTION_TABLE=\fItable\fR
 The contraction table.
 See the
 .B \-c
 .RB "(" "\-\-contraction\-table=" ")"
 option for details.
 .TP
 \fBBRLTTY_MIDI_DEVICE=\fIdevice\fR
 The device to use for the Musical Instrument Digital Interface.
 See the
 .B \-m
 .RB "(" "\-\-midi\-device=" ")"
 option for details.
 .TP
 \fBBRLTTY_PCM_DEVICE=\fIdevice\fR
 The device to use for digital audio.
 See the
 .B \-p
 .RB "(" "\-\-pcm\-device=" ")"
 option for details.
 .TP
 \fBBRLTTY_PREFERENCES_FILE=\fIfile\fR
 The preferences file.
 See the
 .B \-F
 .RB "(" "\-\-preferences\-file=" ")"
 option for details.
 .TP
 \fBBRLTTY_RELEASE_DEVICE=on\fR|\fBoff\fR
 Release the device to which the braille display is connected
 when the current screen or window can't be read.
 See the
 .B \-r
 .RB "(" "\-\-release\-device" ")"
 option for details.
 .TP
 \fBBRLTTY_SCREEN_DRIVER=\fIdriver\fR
 The screen driver.
 See the
 .B \-x
 .RB "(" "\-\-screen\-driver=" ")"
 option for details.
 .TP
 \fBBRLTTY_SCREEN_PARAMETERS=\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the screen driver.
 See the
 .B \-X
 .RB "(" "\-\-screen\-parameters=" ")"
 option for details.
 .TP
 \fBBRLTTY_SPEECH_DRIVER=\fIdriver\fB,\fR...|\fBauto\fR
 The driver for the speech synthesizer.
 See the
 .B \-s
 .RB "(" "\-\-speech\-driver=" ")"
 option for details.
 .TP
 \fBBRLTTY_SPEECH_INPUT=\fIname\fR
 The file system object which gives other applications access to
 .BR brltty 's
 speech driver for text-to-speech conversion.
 See the
 .B \-i
 .RB "(" "\-\-speech\-input=" ")"
 option for details.
 .TP
 \fBBRLTTY_SPEECH_PARAMETERS=\fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the speech synthesizer driver.
 See the
 .B \-S
 .RB "(" "\-\-speech\-parameters=" ")"
 option for details.
 .TP
 \fBBRLTTY_TEXT_TABLE=\fItable\fR
 The text table.
 See the
 .B \-t
 .RB "(" "\-\-text\-table=" ")"
 option for details.
 .SS "The Configuration File"
 Blank lines are ignored.
 If the character
 .B "#"
 occurs on any line then
 all characters from it to the end of that line are treated as a comment.
 .PP
 The following configuration directives are supported:
 .TP
 \fBapi\-parameters \fIname\fB=\fIvalue\fB,\fR...
 Parameters for the application programming interface.
 See the
 .B \-A
 .RB "(" "\-\-api\-parameters=" ")"
 option for details.
 .TP
 \fBattributes\-table \fItable\fR
 The attributes table.
 See the
 .B \-a
 .RB "(" "\-\-attributes\-table=" ")"
 option for details.
 .TP
 \fBbraille\-device \fIdevice\fB,\fR...
 The device to which the braille display is connected.
 See the
 .B \-d
 .RB "(" "\-\-braille\-device=" ")"
 option for details.
 .TP
 \fBbraille\-driver \fIdriver\fB,\fR...|\fBauto\fR
 The driver for the braille display.
 See the
 .B \-b
 .RB "(" "\-\-braille\-driver=" ")"
 option for details.
 .TP
 \fBbraille\-parameters \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the braille display driver.
 See the
 .B \-B
 .RB "(" "\-\-braille\-parameters=" ")"
 option for details.
 .TP
 \fBcontraction\-table \fItable\fR
 The contraction table.
 See the
 .B \-c
 .RB "(" "\-\-contraction\-table=" ")"
 option for details.
 .TP
 \fBmidi\-device \fIdevice\fR
 The device to use for the Musical Instrument Digital Interface.
 See the
 .B \-m
 .RB "(" "\-\-midi\-device=" ")"
 option for details.
 .TP
 \fBpcm\-device \fIdevice\fR
 The device to use for digital audio.
 See the
 .B \-p
 .RB "(" "\-\-pcm\-device=" ")"
 option for details.
 .TP
 \fBpreferences\-file \fIfile\fR
 The preferences file.
 See the
 .B \-F
 .RB "(" "\-\-preferences\-file=" ")"
 option for details.
 .TP
 \fBrelease\-device on\fR|\fBoff\fR
 Release the device to which the braille display is connected
 when the current screen or window can't be read.
 See the
 .B \-r
 .RB "(" "\-\-release\-device" ")"
 option for details.
 .TP
 \fBscreen\-driver \fIdriver\fR
 The screen driver.
 See the
 .B \-x
 .RB "(" "\-\-screen\-driver=" ")"
 option for details.
 .TP
 \fBscreen\-parameters \fIname\fB=\fIvalue\fB,\fR...
 Parameters for the screen driver.
 See the
 .B \-X
 .RB "(" "\-\-screen\-parameters=" ")"
 option for details.
 .TP
 \fBspeech\-driver \fIdriver\fB,\fR...|\fBauto\fR
 The driver for the speech synthesizer.
 See the
 .B \-s
 .RB "(" "\-\-speech\-driver=" ")"
 option for details.
 .TP
 \fBspeech\-input \name\fR
 The file system object which gives other applications access to
 .BR brltty 's
 speech driver for text\-to\-speech conversion.
 See the
 .B \-i
 .RB "(" "\-\-speech\-input=" ")"
 option for details.
 .TP
 \fBspeech\-parameters \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
 Parameters for the speech synthesizer driver.
 See the
 .B \-S
 .RB "(" "\-\-speech\-parameters=" ")"
 option for details.
 .TP
 \fBtext\-table \fItable\fR
 The text table.
 See the
 .B \-t
 .RB "(" "\-\-text\-table=" ")"
 option for details.
 .SS "Driver Specification"
 A braille display or speech synthesizer driver
 must be specified via its identification code:
 .RS
 .TP 4
 .B al
 Alva
 .TP 4
 .B an
 Android
 .TP 4
 .B at
 Albatross
 .TP 4
 .B ba
 BrlAPI
 .TP 4
 .B bc
 BrailComm
 .TP 4
 .B bd
 Braudi
 .TP 4
 .B bl
 BrailleLite
 .TP 4
 .B bm
 Baum
 .TP 4
 .B bn
 BrailleNote
 .TP 4
 .B cb
 CombiBraille
 .TP 4
 .B ce
 Cebra
 .TP 4
 .B cn
 Canute
 .TP 4
 .B dp
 DotPad
 .TP 4
 .B ec
 EcoBraille
 .TP 4
 .B en
 eSpeak-NG
 .TP 4
 .B es
 eSpeak
 .TP 4
 .B eu
 EuroBraille
 .TP 4
 .B fa
 FrankAudiodata
 .TP 4
 .B fl
 FestivalLite
 .TP 4
 .B fs
 FreedomScientific
 .TP 4
 .B fv
 Festival
 .TP 4
 .B gs
 GenericSay
 .TP 4
 .B hd
 Hedo
 .TP 4
 .B hm
 HIMS
 .TP 4
 .B ht
 HandyTech
 .TP 4
 .B hw
 HumanWare
 .TP 4
 .B ir
 Iris
 .TP 4
 .B ic
 Inceptor
 .TP 4
 .B lb
 Libbraille
 .TP 4
 .B lt
 LogText
 .TP 4
 .B mb
 MultiBraille
 .TP 4
 .B md
 MDV
 .TP 4
 .B mm
 BrailleMemo
 .TP 4
 .B mn
 MiniBraille
 .TP 4
 .B mp
 Mikropuhe
 .TP 4
 .B mt
 Metec
 .TP 4
 .B no
 no driver
 .TP 4
 .B np
 NinePoint
 .TP 4
 .B pg
 Pegasus
 .TP 4
 .B pm
 Papenmeier
 .TP 4
 .B sd
 SpeechDispatcher
 .TP 4
 .B sk
 Seika
 .TP 4
 .B sw
 Swift
 .TP 4
 .B th
 Theta
 .TP 4
 .B tn
 TechniBraille Systems Inc.
 .TP 4
 .B ts
 Telesensory Systems Inc.
 .TP 4
 .B vd
 VideoBraille
 .TP 4
 .B vo
 Voyager, Part232 (serial adapter), BraillePen/EasyLink
 .TP 4
 .B vs
 VisioBraille
 .TP 4
 .B vv
 ViaVoice
 .TP 4
 .B xs
 ExternalSpeech
 .PP
 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.
 .PP
 If the single word
 .B auto
 is specified then autodetection is performed
 using only those drivers which are known to be reliable for this purpose.
 .RE
 .SH "SEE ALSO"
 For full documentation, see
 .BR brltty 's
 on-line manual at
 .RB "[" "http://brltty.app/documentation.html" "]."
	.\" @configure_input@
	.\"
	.\" BRLTTY - A background process providing access to the console screen (when in
	.\" text mode) for a blind person using a refreshable braille display.
	.\"
	.\" Copyright (C) 1995-2023 by The BRLTTY Developers.
	.\"
	.\" BRLTTY comes with ABSOLUTELY NO WARRANTY.
	.\"
	.\" This is free software, placed under the terms of the
	.\" GNU Lesser General Public License, as published by the Free Software
	.\" Foundation; either version 2.1 of the License, or (at your option) any
	.\" later version. Please see the file LICENSE-LGPL for details.
	.\"
	.\" Web Page: http://brltty.app/
	.\"
	.\" This software is maintained by Dave Mielke <dave@mielke.cc>.
	.\"
	.TH "BRLTTY" "1" "July 2023" "@PACKAGE_TARNAME@ @PACKAGE_VERSION@" "@PACKAGE_NAME@ User's Manual"
	.SH NAME
	brltty \- refreshable braille display driver for Linux/Unix
	.SH SYNOPSIS
	\fBbrltty \fR[\fIoption\fR ...]
	.SH DESCRIPTION
	.B brltty
	is a background process (daemon)
	which provides access to the console screen (when in text mode)
	for a blind person using a refreshable braille display.
	It drives the braille display,
	and provides complete screen review functionality.
	Some speech capability has also been incorporated.
	.SH OPTIONS
	Options can be passed to
	.B brltty
	in a number of ways.
	From most to least influential, these are:
	.IP 1. 4
	Command Line Options
	.IP 2. 4
	Boot Parameters
	.IP 3. 4
	Environment Variables
	(if the
	.B \-E
	.RB "(" "\-\-environment\-variables" ")"
	option is in effect)
	.IP 4. 4
	The Configuration File
	.IP 5. 4
	Built-in Defaults
	.SS "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.
	.PP
	The following options are supported:
	.TP
	\fB\-a \fItable\fR (\fB\-\-attributes\-table=\fR)
	The path to the attributes table.
	Relative paths are anchored at
	.BR "@TABLES_DIRECTORY@/@ATTRIBUTES_TABLES_SUBDIRECTORY@" "."
	The
	.B ".atb"
	extension is optional.
	The built-in default is
	.BR "@attributes_table@.atb" "."
	.TP
	\fB\-b \fIdriver\fB,\fR...\|\fBauto\fR (\fB\-\-braille\-driver=\fR)
	The driver for the braille display
	(see Driver Specification).
	The built-in default is \fBauto\fR.
	.TP
	\fB\-c \fItable\fR (\fB\-\-contraction\-table=\fR)
	The path to the contraction table.
	Relative paths are anchored at
	.BR "@TABLES_DIRECTORY@/@CONTRACTION_TABLES_SUBDIRECTORY@" "."
	The
	.B ".ctb"
	extension is optional.
	.TP
	\fB\-d \fIdevice\fB,\fR... (\fB\-\-braille\-device=\fR)
	The device to which the braille display is connected.
	The built-in default is \fB@braille_device@\fR.
	.RS
	.PP
	The general form of a braille device specification is
	\fIqualifier\fB:\fIdata\fR.
	For backward compatibility with earlier releases,
	if the qualifier is omitted then
	.B serial:
	is assumed.
	The following device types are supported:
	.TP
	.B Bluetooth
	For a bluetooth device, specify \fBbluetooth:\fIaddress\fR.
	The address must be six two-digit hexadecimal numbers separated by colons, e.g.
	.BR "01:23:45:67:89:AB" "."
	.TP
	.B Serial
	For a serial device, specify \fBserial:\fIdevice\fR.
	The
	.B serial:
	qualifier is optional (for backward compatibility).
	If a relative path is given then it's anchored at
	.B /dev/
	(the usual location where devices are defined on a Unix-like system).
	The following device specifications all refer
	to the primary serial device on Linux:
	.BR "serial:@serial_first_device@" ","
	.BR "serial:/dev/@serial_first_device@" ","
	.BR "@serial_first_device@" ","
	.BR "/dev/@serial_first_device@" "."
	.TP
	.B USB
	For a USB device, specify \fBusb:\fR.
	.B 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.
	.BR "usb:12345" "."
	N.B.:
	The "identification by serial number" feature doesn't work for some models
	because some manufacturers
	either don't set the USB serial number descriptor at all
	or do set it but not to a unique value.
	.PP
	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 interface,
	e.g. both a serial and a USB port.
	.RE
	.TP
	\fB\-e\fR (\fB\-\-standard\-error\fR)
	Write logs to standard error rather than to the system log (useful for debugging).
	.TP
	\fB\-f \fIfile\fR (\fB\-\-configuration\-file=\fR)
	The path to the configuration file.
	Relative paths are anchored at the current working directory.
	The built-in default is
	.BR "@CONFIGURATION_DIRECTORY@/@CONFIGURATION_FILE@" "."
	.TP
	\fB\-h\fR (\fB\-\-help\fR)
	Print a command line usage summary (commonly used options only),
	and then exit.
	.TP
	\fB\-i \fIname\fR (\fB\-\-speech\-input=\fR)
	The file system object
	(FIFO, named pipe, named socket, etc)
	which gives other applications access to
	.BR brltty 's
	speech driver for text-to-speech conversion.
	It's created at start-up and removed at termination.
	Relative paths are anchored at the current working directory.
	The built-in default is
	that the file system object is not created.
	.TP
	\fB\-k \fItable\fR (\fB\-\-keyboard\-table=\fR)
	The path to the keyboard table.
	Relative paths are anchored at
	.BR "@TABLES_DIRECTORY@/@KEYBOARD_TABLES_SUBDIRECTORY@" "."
	The
	.B ".ktb"
	extension is optional.
	.TP
	\fB\-l \fIlevel\fR (\fB\-\-log\-level=\fR)
	The minimum severity level for messages written to the log.
	Any of the following numbers,
	or any abbreviation of their corresponding names,
	may be specified:
	.RS
	.TP 4
	.B 0
	.B emergency
	.TP 4
	.B 1
	.B alert
	.TP 4
	.B 2
	.B critical
	.TP 4
	.B 3
	.B error
	.TP 4
	.B 4
	.B warning
	.TP 4
	.B 5
	.B notice
	.TP 4
	.B 6
	.B information
	.TP 4
	.B 7
	.B debug
	.RE
	.PP
	The built-in default is
	.BR "notice" "."
	.TP
	\fB\-m \fIdevice\fR (\fB\-\-midi\-device=\fR)
	The device to use for the Musical Instrument Digital Interface.
	For ALSA it's \fIclient\fB:\fIport\fR,
	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:
	.RS
	.IP Linux/ALSA 12
	the first available MIDI output port
	.IP Linux/OSS 12
	.B /dev/sequencer
	.RE
	.TP
	\fB\-n\fR (\fB\-\-no\-daemon\fR)
	Remain in the foreground (useful for debugging).
	.TP
	\fB\-o \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-override\-preference=\fR)
	Override a preference setting.
	For the location of the preferences file, see the
	.B \-F
	.RB "(" "\-\-preferences\-file" ")"
	option.
	.TP
	\fB\-p \fIdevice\fR (\fB\-\-pcm\-device=\fR)
	The device to use for digital audio.
	For ALSA it's \fIname\fR[\fB:\fIargument\fB,\fR...].
	For other interfaces it's the full path to an appropriate system device.
	The built-in default is:
	.RS
	.IP FreeBSD 12
	.B /dev/dsp
	.IP Linux/ALSA 12
	.B hw:0,0
	.IP Linux/OSS 12
	.B /dev/dsp
	.IP NetBSD 12
	.B /dev/audio
	.IP OpenBSD 12
	.B /dev/audio
	.IP Qnx 12
	the preferred PCM output device
	.IP Solaris 12
	.B /dev/audio
	.RE
	.TP
	\fB\-q\fR (\fB\-\-quiet\fR)
	Suppress the start-up messages.
	This is done by reducing the default log level
	(see the
	.B \-l
	.RB "(" "\-\-log\-level=" ")"
	option)
	to
	.B warning
	.RB "(" "information"
	if either
	.B \-v
	.RB "(" "\-\-verify" ")"
	or
	.B \-V
	.RB "(" "\-\-version" ")"
	is also specified).
	.TP
	\fB\-r\fR (\fB\-\-release\-device\fR)
	Release the device to which the braille display is connected
	when the current screen or window can't be read.
	.TP
	\fB\-s \fIdriver\fB,\fR...\|\fBauto\fR (\fB\-\-speech\-driver=\fR)
	The driver for the speech synthesizer
	(see Driver Specification).
	The built-in default is \fBauto\fR.
	.TP
	\fB\-t \fItable\fR (\fB\-\-text\-table=\fR)
	The path to the text table.
	Relative paths are anchored at
	.BR "@TABLES_DIRECTORY@/@TEXT_TABLES_SUBDIRECTORY@" "."
	The
	.B ".ttb"
	extension is optional.
	The built-in default is
	.B "@text_table@.ttb"
	(the North American Braille Computer Code).
	.TP
	\fB\-v\fR (\fB\-\-verify\fR)
	Print the start-up messages and then exit.
	This always includes the versions of
	.B brltty
	itself,
	the server side of its application programming interface,
	and each of the selected braille and speech drivers.
	If the
	.B \-q
	.RB "(" "\-\-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 autodetection is performed.
	.TP
	\fB\-x \fIdriver\fR (\fB\-\-screen\-driver=\fR)
	The screen driver.
	The built-in default is operating system appropriate.
	.TP
	\fB\-A \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-api\-parameters=\fR)
	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.
	.TP
	\fB\-B \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR... (\fB\-\-braille\-parameters=\fR)
	Parameters for the braille display driver.
	If the same parameter 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.
	.TP
	\fB\-D \fIdirectory\fR (\fB\-\-drivers\-directory=\fR)
	The path to the directory which contains
	the dynamically loadable driver objects.
	The built-in default is
	.RB "@DRIVERS_DIRECTORY@" "."
	.TP
	\fB\-E\fR (\fB\-\-environment\-variables\fR)
	Recognize environment variables.
	.TP
	\fB\-F \fIfile\fR (\fB\-\-preferences\-file=\fR)
	The path to the preferences file.
	Relative paths are anchored at
	.BR "@UPDATABLE_DIRECTORY@" "."
	The built-in default is
	.BR "@PREFERENCES_FILE@" "."
	.TP
	\fB\-H\fR (\fB\-\-full\-help\fR)
	Print a command line usage summary (all options),
	and then exit.
	.TP
	\fB\-I\fR (\fB\-\-install\-service\fR)
	(Windows only)
	Install
	.B brltty
	as the
	.B BrlAPI
	service so that it will be automatically started when the system is booted,
	and so that applications can know that a
	.B BrlAPI
	server is running.
	.TP
	\fB\-K \fIarg\fR (\fB\-\-keyboard\-properties=\fR)
	Properties of the keyboard.
	.TP
	\fB\-L \fIfile\fR (\fB\-\-log\-file=\fR)
	The file to which log messages are written.
	Relative paths are anchored at the current working directory.
	The default is to send log messages to the system log.
	.TP
	\fB\-M \fIcsecs\fR (\fB\-\-message\-delay=\fR)
	The message hold time in hundredths of a second.
	The built-in default is
	.B 400
	(4 seconds).
	.TP
	\fB\-N\fR (\fB\-\-no\-api\fR)
	Don't start the application programming interface.
	.TP
	\fB\-P \fIfile\fR (\fB\-\-pid\-file=\fR)
	The full path to the process identifier file.
	If this option is supplied,
	.B brltty
	writes its process identifier (pid) into the specified file at start-up.
	The file is removed when
	.B brltty
	terminates.
	.TP
	\fB\-R\fR (\fB\-\-remove\-service\fR)
	(Windows only)
	Remove the
	.B BrlAPI
	service so that
	.B brltty
	will not be automatically started when the system is booted,
	and so that applications can know that no
	.B BrlAPI
	server is running.
	.TP
	\fB\-S \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR... (\fB\-\-speech\-parameters=\fR)
	Parameters for the speech synthesizer driver.
	If the same parameter 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 speech synthesizer driver is being used.
	.TP
	\fB\-T \fIdirectory\fR (\fB\-\-tables\-directory=\fR)
	The path to the directory which contains
	the text, contraction, attributes, keyboard, and input tables.
	The built-in default is
	.RB "@TABLES_DIRECTORY@" "."
	.TP
	\fB\-U \fIdirectory\fR (\fB\-\-updatable\-directory=\fR)
	The path to a directory which contains files that can be updated.
	The built-in default is
	.RB "@UPDATABLE_DIRECTORY@" "."
	.TP
	\fB\-V\fR (\fB\-\-version\fR)
	Print the versions of
	.B 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
	.B \-q
	.RB "(" "\-\-quiet" ")"
	option isn't also specified
	then also print copyright information.
	.TP
	\fB\-W \fIdirectory\fR (\fB\-\-writable\-directory=\fR)
	The path to a directory which can be written to.
	The built-in default is
	.RB "@WRITABLE_DIRECTORY@" "."
	.TP
	\fB\-X \fIname\fB=\fIvalue\fB,\fR... (\fB\-\-screen\-parameters=\fR)
	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.
	.TP
	\fB\-Y \fItext\fR (\fB\-\-start\-message=\fR)
	The text to be shown when the braille driver starts
	and to be spoken when the speech driver starts.
	The built-in default is
	.RB "@PACKAGE_NAME@ @PACKAGE_VERSION@" "."
	.TP
	\fB\-Z \fItext\fR (\fB\-\-stop\-message=\fR)
	The text to be shown when the braille driver stops.
	The built-in default is
	.RB "@PACKAGE_NAME@ stopped" "."
	.SS "Environment Variables"
	The following environment variables are recognized if the
	.B \-E
	.RB "(" "\-\-environment\-variables" ")"
	option is specified:
	.TP
	\fBBRLTTY_API_PARAMETERS=\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the application programming interface.
	See the
	.B \-A
	.RB "(" "\-\-api\-parameters=" ")"
	option for details.
	.TP
	\fBBRLTTY_ATTRIBUTES_TABLE=\fItable\fR
	The attributes table.
	See the
	.B \-a
	.RB "(" "\-\-attributes\-table=" ")"
	option for details.
	.TP
	\fBBRLTTY_BRAILLE_DEVICE=\fIdevice\fB,\fR...
	The device to which the braille display is connected.
	See the
	.B \-d
	.RB "(" "\-\-braille\-device=" ")"
	option for details.
	.TP
	\fBBRLTTY_BRAILLE_DRIVER=\fIdriver\fB,\fR...\|\fBauto\fR
	The driver for the braille display.
	See the
	.B \-b
	.RB "(" "\-\-braille\-driver=" ")"
	option for details.
	.TP
	\fBBRLTTY_BRAILLE_PARAMETERS=\fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the braille display driver.
	See the
	.B \-B
	.RB "(" "\-\-braille\-parameters=" ")"
	option for details.
	.TP
	\fBBRLTTY_CONFIGURATION_FILE=\fIfile\fR
	The configuration file.
	See the
	.B \-f
	.RB "(" "\-\-configuration\-file=" ")"
	option for details.
	.TP
	\fBBRLTTY_CONTRACTION_TABLE=\fItable\fR
	The contraction table.
	See the
	.B \-c
	.RB "(" "\-\-contraction\-table=" ")"
	option for details.
	.TP
	\fBBRLTTY_MIDI_DEVICE=\fIdevice\fR
	The device to use for the Musical Instrument Digital Interface.
	See the
	.B \-m
	.RB "(" "\-\-midi\-device=" ")"
	option for details.
	.TP
	\fBBRLTTY_PCM_DEVICE=\fIdevice\fR
	The device to use for digital audio.
	See the
	.B \-p
	.RB "(" "\-\-pcm\-device=" ")"
	option for details.
	.TP
	\fBBRLTTY_PREFERENCES_FILE=\fIfile\fR
	The preferences file.
	See the
	.B \-F
	.RB "(" "\-\-preferences\-file=" ")"
	option for details.
	.TP
	\fBBRLTTY_RELEASE_DEVICE=on\fR\|\fBoff\fR
	Release the device to which the braille display is connected
	when the current screen or window can't be read.
	See the
	.B \-r
	.RB "(" "\-\-release\-device" ")"
	option for details.
	.TP
	\fBBRLTTY_SCREEN_DRIVER=\fIdriver\fR
	The screen driver.
	See the
	.B \-x
	.RB "(" "\-\-screen\-driver=" ")"
	option for details.
	.TP
	\fBBRLTTY_SCREEN_PARAMETERS=\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the screen driver.
	See the
	.B \-X
	.RB "(" "\-\-screen\-parameters=" ")"
	option for details.
	.TP
	\fBBRLTTY_SPEECH_DRIVER=\fIdriver\fB,\fR...\|\fBauto\fR
	The driver for the speech synthesizer.
	See the
	.B \-s
	.RB "(" "\-\-speech\-driver=" ")"
	option for details.
	.TP
	\fBBRLTTY_SPEECH_INPUT=\fIname\fR
	The file system object which gives other applications access to
	.BR brltty 's
	speech driver for text-to-speech conversion.
	See the
	.B \-i
	.RB "(" "\-\-speech\-input=" ")"
	option for details.
	.TP
	\fBBRLTTY_SPEECH_PARAMETERS=\fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the speech synthesizer driver.
	See the
	.B \-S
	.RB "(" "\-\-speech\-parameters=" ")"
	option for details.
	.TP
	\fBBRLTTY_TEXT_TABLE=\fItable\fR
	The text table.
	See the
	.B \-t
	.RB "(" "\-\-text\-table=" ")"
	option for details.
	.SS "The Configuration File"
	Blank lines are ignored.
	If the character
	.B "#"
	occurs on any line then
	all characters from it to the end of that line are treated as a comment.
	.PP
	The following configuration directives are supported:
	.TP
	\fBapi\-parameters \fIname\fB=\fIvalue\fB,\fR...
	Parameters for the application programming interface.
	See the
	.B \-A
	.RB "(" "\-\-api\-parameters=" ")"
	option for details.
	.TP
	\fBattributes\-table \fItable\fR
	The attributes table.
	See the
	.B \-a
	.RB "(" "\-\-attributes\-table=" ")"
	option for details.
	.TP
	\fBbraille\-device \fIdevice\fB,\fR...
	The device to which the braille display is connected.
	See the
	.B \-d
	.RB "(" "\-\-braille\-device=" ")"
	option for details.
	.TP
	\fBbraille\-driver \fIdriver\fB,\fR...\|\fBauto\fR
	The driver for the braille display.
	See the
	.B \-b
	.RB "(" "\-\-braille\-driver=" ")"
	option for details.
	.TP
	\fBbraille\-parameters \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the braille display driver.
	See the
	.B \-B
	.RB "(" "\-\-braille\-parameters=" ")"
	option for details.
	.TP
	\fBcontraction\-table \fItable\fR
	The contraction table.
	See the
	.B \-c
	.RB "(" "\-\-contraction\-table=" ")"
	option for details.
	.TP
	\fBmidi\-device \fIdevice\fR
	The device to use for the Musical Instrument Digital Interface.
	See the
	.B \-m
	.RB "(" "\-\-midi\-device=" ")"
	option for details.
	.TP
	\fBpcm\-device \fIdevice\fR
	The device to use for digital audio.
	See the
	.B \-p
	.RB "(" "\-\-pcm\-device=" ")"
	option for details.
	.TP
	\fBpreferences\-file \fIfile\fR
	The preferences file.
	See the
	.B \-F
	.RB "(" "\-\-preferences\-file=" ")"
	option for details.
	.TP
	\fBrelease\-device on\fR\|\fBoff\fR
	Release the device to which the braille display is connected
	when the current screen or window can't be read.
	See the
	.B \-r
	.RB "(" "\-\-release\-device" ")"
	option for details.
	.TP
	\fBscreen\-driver \fIdriver\fR
	The screen driver.
	See the
	.B \-x
	.RB "(" "\-\-screen\-driver=" ")"
	option for details.
	.TP
	\fBscreen\-parameters \fIname\fB=\fIvalue\fB,\fR...
	Parameters for the screen driver.
	See the
	.B \-X
	.RB "(" "\-\-screen\-parameters=" ")"
	option for details.
	.TP
	\fBspeech\-driver \fIdriver\fB,\fR...\|\fBauto\fR
	The driver for the speech synthesizer.
	See the
	.B \-s
	.RB "(" "\-\-speech\-driver=" ")"
	option for details.
	.TP
	\fBspeech\-input \name\fR
	The file system object which gives other applications access to
	.BR brltty 's
	speech driver for text\-to\-speech conversion.
	See the
	.B \-i
	.RB "(" "\-\-speech\-input=" ")"
	option for details.
	.TP
	\fBspeech\-parameters \fR[\fIdriver\fB:\fR]\fIname\fB=\fIvalue\fB,\fR...
	Parameters for the speech synthesizer driver.
	See the
	.B \-S
	.RB "(" "\-\-speech\-parameters=" ")"
	option for details.
	.TP
	\fBtext\-table \fItable\fR
	The text table.
	See the
	.B \-t
	.RB "(" "\-\-text\-table=" ")"
	option for details.
	.SS "Driver Specification"
	A braille display or speech synthesizer driver
	must be specified via its identification code:
	.RS
	.TP 4
	.B al
	Alva
	.TP 4
	.B an
	Android
	.TP 4
	.B at
	Albatross
	.TP 4
	.B ba
	BrlAPI
	.TP 4
	.B bc
	BrailComm
	.TP 4
	.B bd
	Braudi
	.TP 4
	.B bl
	BrailleLite
	.TP 4
	.B bm
	Baum
	.TP 4
	.B bn
	BrailleNote
	.TP 4
	.B cb
	CombiBraille
	.TP 4
	.B ce
	Cebra
	.TP 4
	.B cn
	Canute
	.TP 4
	.B dp
	DotPad
	.TP 4
	.B ec
	EcoBraille
	.TP 4
	.B en
	eSpeak-NG
	.TP 4
	.B es
	eSpeak
	.TP 4
	.B eu
	EuroBraille
	.TP 4
	.B fa
	FrankAudiodata
	.TP 4
	.B fl
	FestivalLite
	.TP 4
	.B fs
	FreedomScientific
	.TP 4
	.B fv
	Festival
	.TP 4
	.B gs
	GenericSay
	.TP 4
	.B hd
	Hedo
	.TP 4
	.B hm
	HIMS
	.TP 4
	.B ht
	HandyTech
	.TP 4
	.B hw
	HumanWare
	.TP 4
	.B ir
	Iris
	.TP 4
	.B ic
	Inceptor
	.TP 4
	.B lb
	Libbraille
	.TP 4
	.B lt
	LogText
	.TP 4
	.B mb
	MultiBraille
	.TP 4
	.B md
	MDV
	.TP 4
	.B mm
	BrailleMemo
	.TP 4
	.B mn
	MiniBraille
	.TP 4
	.B mp
	Mikropuhe
	.TP 4
	.B mt
	Metec
	.TP 4
	.B no
	no driver
	.TP 4
	.B np
	NinePoint
	.TP 4
	.B pg
	Pegasus
	.TP 4
	.B pm
	Papenmeier
	.TP 4
	.B sd
	SpeechDispatcher
	.TP 4
	.B sk
	Seika
	.TP 4
	.B sw
	Swift
	.TP 4
	.B th
	Theta
	.TP 4
	.B tn
	TechniBraille Systems Inc.
	.TP 4
	.B ts
	Telesensory Systems Inc.
	.TP 4
	.B vd
	VideoBraille
	.TP 4
	.B vo
	Voyager, Part232 (serial adapter), BraillePen/EasyLink
	.TP 4
	.B vs
	VisioBraille
	.TP 4
	.B vv
	ViaVoice
	.TP 4
	.B xs
	ExternalSpeech
	.PP
	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.
	.PP
	If the single word
	.B auto
	is specified then autodetection is performed
	using only those drivers which are known to be reliable for this purpose.
	.RE
	.SH "SEE ALSO"
	For full documentation, see
	.BR brltty 's
	on-line manual at
	.RB "[" "http://brltty.app/documentation.html" "]."