The "Active Window" toggle option in device settings allows you to toggle the hours within which your specified device will display playlist content. Beyond a device's active hours, a black screen is displayed.
To configure the device's "Active Window":
Click the "Devices" icon from the left hand taskbar.
Select the device(s) you'd like to apply the active window to.
Navigate to the "Settings" tab for this device on the right, and toggle on the "Active Window" switch on.
This will reveal an option to set the chosen devices "Active Hours". Set these hours from xx:xx to xx:xx as desired. You can also select specific days on which you wish to apply this active window if active hours differ per day.
☝️ Note: This feature is only available to Plus, Network and Enterprise customers.