Braille - Form

Form

Braille can be seen as the world's first binary encoding scheme for representing the characters of a writing system. The system as devised by Braille consists of two parts:

1. A character encoding for mapping characters of the French alphabet to tuples of six bits or dots.
2. A way of physically representing six-bit characters as raised dots in a braille cell.

Within an individual cell, the possible dot positions are organized into two columns of three positions each. A raised dot can appear in any of the six positions to form sixty-four (26) possible subsets, including the arrangement in which there are no raised dots. For reference purposes, a particular arrangement may be described by naming the positions where dots are raised, the positions being universally numbered 1 to 3, from top to bottom, on the left, and 4 to 6, from top to bottom, on the right. For example, dots 1-3-4 (⠍) would describe a cell with three dots raised, at the top and bottom in the left column and on top of the right column, i.e., the letter m. The lines of horizontal braille text are separated by a space, much like visible printed text, so that the dots of one line can be differentiated from the braille text above and below. Punctuation is represented by its own unique set of characters.Today different braille codes (or code pages) are used to map character sets of different languages to the six bit cells. Different braille codes are also used for different uses like mathematics and music. However, because the six-dot braille cell only offers 64 patterns (26, including the space), many braille characters have different meanings based on their context. That is, character mapping is not one-to-one.

In addition to simple encoding, modern braille transcription uses contractions to increase reading speed. (See: Contracted braille)