VoiceOver and Braille Display Question

[Richie Gardenhire]

Hello, I have never used a braille display with VoiceOver, and my  
question is, do the supported braille devices/displays have associated  
chords which are recognized by VoiceOver?  In other words, can the  
braille device/display, in question, be used as a command facilitater  
or must these commands be performed directly from the Apple keyboard?   
Richie Gardenhire, Anchorage, Alaska.