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
Writing system alphabet, or were directly inspired by its design. The first true alphabet is the Greek script which consistently represents vowels since 800 BC. The Latin alphabet, a direct descendant, is by far the most common writing system in use. Several approaches have been taken to classify writing systems, the most common and basic one is a broad division into three categories: "logographic", "syllabic", and "alphabetic" (or "segmental"); however, all three may be found in any given writing system in varying proportions, often making it difficult to categorise a system uniquely. The term "complex system" is sometimes used to describe those