If one of those devices happens to be Sony’s DualShock 4 controller, [DoganM95] has the fix for you. Sony wisely put the controller’s original micro USB connector on a separate PCB so it could ...
In fact, if you have been wondering what the EXT port (or Extension port) on your DualShock 4 does, don't bother turning to the controller's instruction manual. It's not even mentioned.