Re: Braille keyboard question. e


Richard Holloway
 

Yes— that can work fine for many users, the key-rollover issue can come into play with that program as well. You have to check on a keyboard-by-keyboard basis to see which ones can deal with what you are entering. You might even have to bypass the built-in keyboard on a laptop with an external plugged in… Some keyboards can only rollover two keys, as strange as that may sound. (Some can still work with CTRL+ALT+DEL but have a general 2 key limit.) If you press a third, you will either get a ghosted fourth character, or I believe some will disregard the first pressed at the instant the third switches to being “down”, while other ignore the last down until the first are released. On the other extreme, I have read that some keyboards will support an unlimited number of keys being pressed at once, but I think that is only certain old PS2 designs. I have yet to see where a USB keyboard is unlimited, though 6 keys is pretty common to work.

For just plain old un-contracted braille, you should be fine if you can rollover 4 keys at once for everything except for a Braille Q and a Braille Y, UNLESS you also have the ghosting issues, where some pairings of 3 (or more) keys can create one or more extra (virtual) input stroke(s) that you didn’t actually type, and since this is with only certain groupings, the problem may not show up right away. Still, I suspect most users want to have all 26 letters available, if not contractions too…(a contracted “and”, “of”, or “for” would be an issue as well if 4 is the limit.)

Many keyboards work just fine with 4, 6, or even more characters being pressed at once, but again, this is a hardware (and/or USB driver) limitation that will vary from one keyboard to the next…. I’m not an expert on this stuff my ANY means. I just don’t want people assuming that what works for others will work for them, because it varies a great deal between hardware setups.

On Apr 14, 2014, at 9:13 AM, Sally Hagarty <shagarty@...> wrote:

I use the free program Perky Duck from Duxbury. My FDS and JKL keys are the Braille keys . Documents are saved as .dbt files. I email my Braille lessons to my Hadley School instructor using this program .


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Sally A Hagarty,MST, ATP
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