When the Parrot Skycontroller 3 is powered on, its LED status indicator gives you an instant visual indication:
Flashing green:
Skycontroller 3 update in progress
Alternating light blue and dark blue:
Connecting to ANAFI series drone
Flashing light blue:
No drone configured or wrong WPA key
Steady dark blue:
Connected to ANAFI series drone
Alternating purple and dark blue:
Autonomous flight in progress
Alternating red and any other color:
Low battery alert (drone, Skycontroller 3 or both) or RTH alert