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
National Federation of the Blind v. Target Corp. the Web Content Accessibility Guidelines or the Architectural and Transportation Barriers Compliance Board's Section 508 Amendment to the Rehabilitation Act of 1973 standards, specifically encouraging Target to adopt the alt attribute for clickable images featured on the website. In its petition, NFB alleged that in one instance, when a blind user visiting this website selected an image of a Dyson vacuum cleaner using his or her tab key, the voice synthesizer on the computer would say "Link GP browse dot html reference zero six zero six one eight nine six three eight one eight zero seven two nine seven three