[orca-list] Checking for n-key rollover

[Rakesh 'arky' Ambati <rakesh_ambati yahoo com>]

Hi,

I heard that if you computer supports n-key rollover then you can type braille like we do on a portable 
braille note taker like Baum Pronto!. 

Doesn't anyone know how to check for the n-key rollover support in gnu/Linux.
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 N-key rollover
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Certain high-end keyboards have "n-key rollover". This means that each key is scanned completely 
independently by the keyboard hardware, so that each keypress is correctly detected regardless of how many 
other keys are being pressed or held down at the time. 

However, to reduce cost and design complexity, most keyboards do not isolate all keys in this way. Instead, 
they use a matrix of key switches, without any isolation diodes, that assumes that only a limited number of 
keys will be held down at any given time.

Most music keyboards use isolation diodes in their keyboard matrix to implement full N-key rollover, making 
them immune to both key ghosting and key jamming.

3-key rollover

A keyboard with "3-key rollover" can reliably detect any two keys used simultaneously; in other words, a user 
can hold down any key on the keyboard and press a second key, and be sure that the keypress is correctly 
detected by the computer. However, if the user holds down two and attempts to strike a third, the keypress 
may be misinterpreted depending on what key is pressed.

3-key rollover is considered essential for English touch typing. 

> From Wikipedia

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TIA

--arky
Rakesh 'arky' Ambati 
Blog [ http://playingwithsid.blogspot.com ]


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