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
Six-bit character code (1965). FIELDATA was a seven-bit code (with optional parity) of which only 64 code positions (occupying six bits) were formally defined. A variant was used by UNIVAC's 1100-series computers. Treating the code as a six-bit code these systems used a 36-bit word (capable of storing 6 such reduced FIELDATA characters). Braille characters are represented using six dot positions, arranged in a rectangle. Each position may contain a raised dot or not, so Braille can be considered to be a six-bit binary code. Transmission of binary data over systems which are designed for text only can sometimes introduce problems. For example,