Night writing visited the National Institute for the Blind in Paris, France, where he met Louis Braille. Braille identified the major failing of the code, which was that the human finger could not encompass the whole symbol without moving and so could not move rapidly from one symbol to another. His modification was to use a six-dot cell, the Braille system that revolutionized written communication for the visually impaired. Night writing Night writing, a.k.a. sonography, was a system of code that used symbols of twelve dots arranged as two columns of six dots embossed on a square of paperboard, and is now
Blind Approach Beacon System to fly left or right and indeed up or down with a co-located glidepath (328.6 to 335.4 MHz) equipment. See instrument landing system for further details. Blind Approach Beacon System A blind approach beacon system or beam approach beacon system (BABS) is an automatic radar landing system developed in the early 1940s. It is a responder (or transponder) mounted in a Hillman van and placed at the end of the runway. In some cases fixed sites were installed and by the mid-1950s Standard 9 vans were in use. It was interrogated by a "Rebecca" unit mounted in an aircraft. It