These are braille terminals that can read the screen memory directly in a normal text mode. It is possible to use it to work with Linux for almost all of the things that a seeing user can do on the console, including installation. However, it has a problem with the scrolling of the normal Linux kernel, so a kernel patch needs to be applied. See Patching the Kernel for Braillex and Brailloterm.
The Braillex is a terminal which is designed to read directly from the Screen memory, thus getting round any problems with MS-DOS programs which don't behave strangely. If you could see it on screen, then this terminal should be able to display it in braille. In Linux, unfortunately, screen handling is done differently from MS-DOS, so this has to be changed somewhat.
To get this terminal to work, you have to apply the patch given below in section Patching the Kernel. Once this is done. The Braillex becomes one of the most convenient ways to use Linux as it allows all of the information normally available to a seeing person to be read. Other terminals don't start working until the operating system has completely booted.
The Braillex is available with two arrangements of braille cells (80x1 or 40x2) and there is a model, called the IB 2-D which also has a vertical bar to show information about all of the lines of the screen (using 4 programmable dots per screen line)
Price: 8,995 UKP (pounds sterling) or 11495 UKP for 2-D Manufacturer: Alphavision Limited (UK) Suppliers: ????
``What is Brailloterm?
It's a refresh-able display braille, made by KTS Kommunikations-Technik Stolper GmbH. It has 80 braille cells in an unique line. Each cell has 8 dots that are combined(up/down) to represent a character. By default, Brailloterm shows me the line in which the screen cursor is. I can use some functions in Brailloterm to see any line in the screen.''
Jose Vilmar Estacio de Souza <jvilmar@embratel.net.br>
Jose then goes on to say that the terminal can also use the serial port under DOS but that it needs a special program. I don't know if any of the ones for Linux would work.
As with Braillex, this needs a special patch to the kernel work properly. See section Patching the Kernel.
Price: about 23.000,- DM / $ 15.000, Manufacturer: Kommunikations-Technik Stolper GmbH Suppliers: ????
This probably also applies to any other terminals which read directly from screen memory to work under MS-DOS. Mail me to confirm any terminals that you find work.
I am told this patch applies to all Kernels version 1.2.X. It
should also work on all Kernel versions from 1.1.X to 1.3.72, with
just a warning from patch (I've tested that the patch applies to
1.3.68 at least). From 1.3.75 the patch is no longer needed
because the Kernel can be configured not to scroll using `linux
no-scroll' at the LILO prompt. See the Boot Prompt HOWTO for more
details.
*** drivers/char/console.c~ Fri Mar 17 07:31:40 1995
--- drivers/char/console.c Tue Mar 5 04:34:47 1996
***************
*** 601,605 ****
static void scrup(int currcons, unsigned int t, unsigned int b)
{
! int hardscroll = 1;
if (b > video_num_lines || t >= b)
--- 601,605 ----
static void scrup(int currcons, unsigned int t, unsigned int b)
{
! int hardscroll = 0;
if (b > video_num_lines || t >= b)
To apply it:
patch < patch-file
Apply those patches and you should be able to use the braille terminal as normal to read the Linux Console.
Put in words, the patch just means `change the 1 to a 0 in the
first line of the function scrup which should be near line 603 in the
file drivers/char/console.c'. The main thing about patch is that
program understands this, and that it knows how to guess what to do
when the Linux developers change things in that file.
If you want to use a more modern kernel with completely disabled scrolling, (instead of the boot prompt solution I already mentioned), please use the following patch. This does not apply to kernels earlier than 1.3.75.
*** console.c~ Fri Mar 15 04:01:45 1996
--- console.c Thu Apr 4 13:29:48 1996
***************
*** 516,520 ****
unsigned char has_wrapped; /* all of videomem is data of fg_console */
static unsigned char hardscroll_enabled;
! static unsigned char hardscroll_disabled_by_init = 0;
void no_scroll(char *str, int *ints)
--- 516,520 ----
unsigned char has_wrapped; /* all of videomem is data of fg_console */
static unsigned char hardscroll_enabled;
! static unsigned char hardscroll_disabled_by_init = 1;
void no_scroll(char *str, int *ints)
The principle of operation of these terminal is very close to that of a CRT terminal such as the VT100. They connect to the serial port and the computer has to run a program which sends them output. At present there is one known (BRLTTY, see section BRLTTY) and one rumoured program for Linux (Braille enhanced screen.. no details yet).
This is the recommended braille terminal to use with version 0.22BETA of the BRLTTY software. It comes in three versions with 25, 45 or 85 braille cells.
Price: around 4600 UKP for the 45 cell model ... Manufacturer: Tieman B.V. Suppliers: Concept Systems, Nottingham, England (voice +44 115 925 5988)
These will be supported in the forthcoming version 1.0 of
BRLTTY.
This is more a portable computer than a terminal. It could, however, be used with BRLTTY version 0.22 (but not newer versions) as if it was a normal braille terminal. Unfortunately, many of the features available with the CombiBraille cannot be used with the Braille Lite. This means that it should be avoided for Linux use where possible.
Price: $3,395.00 Manufacturer: Blazie Engineering Suppliers: ????
Speech synthesisers normally connect to the serial port of a PC. Useful features include
This is a hardware speech synthesiser. It is recommended for use with Emacspeak and in fact the DECTalk range are the only speech synthesisers which work with that packages at present. This synthesiser has every useful feature that I know about. The only disadvantage that I know of at present is price.
Price: $1195.00
Manufacturer: Digital Equipment Corporation
Suppliers: Many. I'd like details of those with Specific Linux
support / delivering international or otherwise of note only
please. Otherwise refer to local organisations.
Digital themselves or the Emacspeak WWW pages.