Braille

Braille is a family of writing systems for the blind, in many languages. The Braille symbols consist of six or eight raised dots each, in two columns. Both sets are included in Unicode. The Braille symbols are not an alphabet in themselves, but can be mapped to many different alphabets in different ways. Different countries commonly use different mappings even for the same alphabet.

Six-dot braille has 64 possible combinations, including blank. This is ample for a single-case Latin alphabet, ten digits, various punctuation symbols, and several other symbols, including some used to mark abbreviations or change encoding modes. By changing modes, one can also change to a different encoding. For example, music written in Braille can be included within text. However, it is impractical to try to squeeze both upper and lower case into a six-dot Braille encoding. Eight-dot Braille has 256 combinations, just like 8-bit bytes on computers, and can therefore map to any 8-bit character encoding directly.

Braille input into a computer can be done by touch typing normally but displaying the input material in a Braille font. There are also special-purpose six-key and eight-key Braille input devices where each symbol is entered by pressing the keys for its dots simultaneously. There are Braille output devices of several kinds, including embossers to create traditional raised Braille dots on heavy paper, and interactive displays that raise pins to create the dots for reading.

Unfortunately Braille hardware is still rather expensive. Braille publishing is heavily subsidized by societies for the blind, and by some governments.

There is a list of Unicode Braille fonts on David McCreedy's Gallery of Unicode Fonts page.