Just installed Essential

[Rogerowl]

What is the difference between Device on/off and Device armed/unarmed?

how does either affect operation

[jguerdat]

It depends on how your system is configured. If connected to a base or hub, using the Disarmed mode turns all cameras off. If connected to your WiFi (so it's a device all by itself), disarmed and off are the same thing. Using the On/Off slider controls just the one camera.