I recommend that you read the posts linked above (if German is not one of your strengths use google translate and pester me with questions afterwards
. If it
is one of your strengths you may ask any question anyway
).
"dedicated power supply": No, the 5V 100mA provided by USB are quite sufficient for the LED backlight (5 LEDs at 20mA for each of the two BUs). That's one of the reasons I used the BU836As: The BU836X does not have pins to grab these 5V from.
"looks like cooling slots": No, that are two self made plug-fields for the button matrixes of the BU836As (see Bodnar's site for details). I've used the BU836As rather than BU836Xs because with 72 buttons and 16 axes cableing becomes a space problem (=144 + 48 wires). With the A's button matrix it's just 7 wires for every six buttons.
Artist
Edit: Orthography