Computer Braille Code Explained

Computer Braille is an adaptation of braille for precise representation of computer-related materials such as programs, program lines, computer commands, and filenames. Unlike standard 6-dot braille scripts, but like Gardner–Salinas braille codes, this may employ the extended 8-dot braille patterns.

There are two standards of representation of computer code with braille:

1) The Computer Braille Code as defined by the Braille Authority of North America.^[1] However, since January 2016 it is no longer official in the US and replaced by Unified English Braille (UEB). It employs only the 6-dot braille patterns to represent all printing code points of ASCII. It is virtually identical to Braille ASCII, a system of representation of braille with ASCII characters, which goal is mirrored to the Computer Braille Code. To represent ASCII code points 0x60, 0x7B, 0x7C, 0x7D, 0x7E as well as capital letters the 4-5-6 character is used as the shift indicator or modifier. Thus, (grave accent, 0x60) is represented by, where is assigned to (at sign, 0x40). In other words, either adds (for punctuation) or subtracts (for letters) 32 to or from the ASCII value of the following character. Unlike Braille ASCII (underscore, 0x5F) is represented by .

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2) The Braille Computer Notation as defined by the Braille Authority of the United Kingdom.^[2] It uses 8-dot patterns to represent 256 different values so arbitrary byte data can be written in Braille.The 8-dot code is designed that its 6-dot subset is identical to the 6-dot code. The remainder are assigned by the following rules:

adding dot 7 subtracts 32 from the ASCII value;
adding dot 8 adds 128 to the ASCII value;

The dot-5 character is used as a universal modifier.

The following table assumes the 8-bit data is encoding text in the CP437 character set used on the IBM PC.

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References

Book: Computer Braille Code: 2000 Revision. 2000. Braille Authority of North America.
Book: Braille Computer Notation. 2006. Braille Authority of the United Kingdom (Computer Committee). https://web.archive.org/web/20200801050601if_/https://www.ukaaf.org/wp-content/uploads/2015/05/Braille-Computer-Notation-PDF.pdf. 2020-08-01. dead.