Hardware braille devices
Installation CD usually start with the linux framebuffer enabled, for being able to display asian fonts, for instance. This poses problems with hardware screen readers, since this is not a text mode. You can disable that by appending video=vga16:off to the kernel parameter list (at the syslinux or lilo prompt, for instance). You should also prevent the use of scrolling capacities of the video board by appending the no-scroll option.
Shrink the text console
The linux console is usually 80 characters wide. Some braille device only have for instance 60 characters. This hence doesn't match good. But you can run
stty cols 60
to make the linux console shrink to 60 characters. Every program will then use this as screen width, and their output will hence fit in a single braille line !
Some screens (like laptop ones) will actually expand the text for fitting it to the screen. This can hence be used as a magnifying facility for the console.
Note: before linux 2.6.14, this would shuffle screen display a bit, but don't worry, it won't break it.