Smart Keyboards for Device Control and Data Entry
From: NASA Tech Brief Insider - 07/07/2008

A keyboard features movable keys in different directions, allowing each key
to generate multiple and distinct predetermined signals that are mapped to
alphanumerics, symbols, functions, and operations. Each key can carry out
multiple functions. Keyboards with these type of keys require fewer keys, so
they can be physically smaller without reducing either the size of the actual
key or the amount of space around the key. Data entry can be performed
without over-striking adjacent keys as frequently happens in crowded, smaller
keyboards with undersized keys. Practical for devices and instruments that
need a keyboard for data entry or control, but have limited space. 

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http://www.nexttechs.com/abpi/tech.asp?id=3384