The Quest for Access to Science by People with Print Impairments, by John A. Gardner
DotsPlus was originally defined as a tactile font in which the lower case alphabet was standard braille, and the upper case alphabet was defined as eight-dot braille characters familiar to users of on-line computer braille displays. Eight dot braille cells have an additional row on the bottom, and the lower left dot is now accepted as the capital letter indicator.
The European Computer Braille numbers were adopted as DotsPlus numbers. These braille cells are closely related to the letters a-j used in literary braille number mode but do not conflict with any cell in English Grade 1 (uncontracted) braille.
DotsPlus punctuation marks are small graphic symbols that feel very much likestandard braille punctuation marks. However unlike the braille symbols they are distinguishable from letters when out of context. In Braille a subscript letter a is indistinguishable from a comma, but a DotsPlus reader can distinguish the two cases.
Most other DotsPlus symbols are tactile graphic representations with shapes much like the print symbols.
Many braille readers found the eight-dot braille characters difficult to read, and a second DotsPlus font has recently been defined that uses double six-dot cells instead of eight-dot characters. A capital letter is represented in this font exactly as it would be in literary braille. This font is less space-efficient than the original DotsPlus font that was based on eight-dot braille, but it feels more familiar to children and novice readers.
More detailed information, including pictures illustrating DotsPlus and instructions for downloading DotsPlus fonts and macros can be found on the SAP DotsPlus description page.