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
Dot matrix be resized, as with font typefaces. For maximum image quality using only dot matrix fonts, it would be necessary to store a separate dot matrix pattern for the many different potential point sizes that might be used. Instead, a single group of vector shapes is used to render all the specific dot matrix patterns needed for the current display or printing task. All points addressable (APA), or pixel addressable, in the context of a dot matrix on a computer monitor or any display device consisting of a pixel array, refers to an arrangement whereby bits or cells can be individually