Hi,
On my side, I’m using the Pi-Switch from nanomesher
(see my post here : My high-end streamer)
It has for effect to send an interrupt to the RPi, asking him to make a software shutdown, before cutting down the power supply through the help of a relay.
It works like a charm.
But I don’t know the X400, so I’m not sure of what has to be taken care of.
Florian