Power box question

So if I plug in the axis control box on my q204 without having all the cables all hooked up the power does not stay on. I was trying to test the software and see if I could get it out of demo mode so I plugged it in To the usb ect and yea every time I hit the green power button the power would only stay on while I held the button. Anyone know what that is? I was doing it this way because I don’t have a 240 line in yet and I want to make sure all this shit works before I invest in everything I need for wiring.