The DIC-23216 switches to 'Power Saving Mode' as soon as you disconnect the power cable; it then starts using its battery.
It comes out of this mode as soon as someone pushes the 'call'-button on the outdoor unit.
If the DIC-23216 is connected with the power cable that comes with it, it will come out of 'Power Saving Mode' after a short while. It can then be used as a camera.
This solution is valid for DIC-23216 - DIC-23216UK