On an external call, the screen lights ... We can talk to the caller ... But when you press the door release button to open ... The screen turns off instantly . This feature seems to be a connection error so it seems ABSURD and devoid of any sense. This remains frustrating because the other person has failed to open the door ... It is impossible to resume the call ... It invariably ended up opening yourself .... ZERO!
If I had read the manual before, I would not buy this product