https://en.wikipedia.org/wiki/Braille
Braille is a tactile writing system and is used by the blind and severely visually impaired, as they cannot read blackletter or can read it only with difficulty. It was developed by Frenchman Louis Braille in 1825. The script consists of dot patterns that are usually pressed into paper from behind and can be felt as raised areas in the front with the fingertips.
A dot grid of 3×2 dots is used to encode letters and groups of letters. The six dots can be used to represent 64 different characters. To extend the character range, for example, upper and lower case, special characters are defined, pointing out corresponding switches or double assignments.
Beyond the 26 letters of the Latin alphabet and the 10 digits, additional letters and letter combinations were defined depending on the language and adopted as national standards.
An overview can be found in the World Braille Usage, Third Edition (pharmabraille.com).
With the advent of electronic data processing, the Braille system was expanded to 8 points and a standard was defined that was used in computing: Computer Braille or Eurobraille. Eurobraille refers to the mapping of the 256 characters of a Western European character set to the 256 possible 8-point Braille characters of Computer Braille. The character set ISO 8859-1 is used.
The exact assignments of the 8-dot Braille to the 8-bit code are defined in the DIN standard 32982.
Alexander Fakoó
Alexander Fakoó has extended Braille to nine dots.
Fakoo writing (Fakoo for short – written F a k o o and emphasized on the last syllable) is intended to serve as a link between 6-dot Braille and blackletter so that blind, visually impaired and sighted people can communicate better with each other. There are many new applications, particularly in the public sector, due to the greater acceptance of sighted people. Fakoo would also be an alternative to Braille for those who cannot cope with Braille.