Hi,
You could try the following....
1) On the Parent Unit from the menu select the "dB" option and select the red cross to disable this feature for over night use.
2) On the Parent Unit from the menu select the screen saver option and set this to for example 1 minute, this means the screen will stop showing pictures after 1 minute of inactiviy and to reactive you press a button on the Parent Unit.
3) Set the speak volume on the Parent Unit to level 4 for example.
These settings will hopefully allow you to hear your baby making sounds, but will not allow the screen to come on when the Baby moves around.
Remember to change the settings for daytime use....
Hope this helps?
Martin
