History
The base of a refreshable braille display is a pure braille terminal. There, the input is performed by two sets of three keys plus a space bar (as in the Perkins Brailler), while output is via a refreshable braille display consisting of a row of electromechanical character cells, each of which can raise or lower a combination of six (or in some cases, eight) round-tipped pins. Other variants exist that use a conventional QWERTY keyboard for input and braille pins for output, as well as input-only and output-only devices. In 1951, David Abraham, a woodworking teacher at Perkins, created a portable braille terminal.
Read more about this topic: Refreshable Braille Display
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