USB
The USB port is for charging only. the PMA450, like all of their other audio panels, aren't connected to computers for configurations. The configurations that pilots most often adjusted, are controlled with the 3 key/graphics display interface.
The PMA450 has a superset of capabilities of the PMA8000 series. IntelliAudio, human interface, and the advanced capabilities of the Bluetooth are just some of the enhancements.
sincerely.
Mark Scheuer