If you prefer not to use the included on off switch, you can make a simple modification to have the focbox unity go into "always on mode"
This mode is required if you plan to use a loop key as a power on/off switch.
The modification is really easy, Simply short the pins on the switch connector! As indicated by the yellow highlight
TIP: You can make a little plug from the switch connector if you think that is easier. Then when you remove the plug the modification is also removed.