Chorded keyboard (a writing system for the blind) uses either 6 or 8 tactile 'points' from which all letters and numbers are formed. When Louis Braille invented it, it was produced with a needle holing successively all needed points in a cardboard sheet. In 1892, Frank Haven Hall, superintendent of the Illinois Institute for the Education of the Blind, created the Hall Braille Writer, which was like a typewriter with 6 keys, one for each dot in a braille cell. The Perkins Brailler, first manufactured in 1951, uses a 6-key chord keyboard (plus a spacebar) to produce braille output, and has been
Louis Braille its form and maximizing its efficiency. He made uniform columns for each letter, and he reduced the twelve raised dots to six. He published his system in 1829, and by the second edition in 1837 he had discarded the dashes because they were too difficult to read. Crucially, Braille's smaller cells were capable of being recognized as letters with a single touch of a finger. Braille created his own raised-dot system by using an awl, the same kind of implement which had blinded him. In the process of designing his system, he also designed an ergonomic interface for using it,