So the goal is to identify what I marked as “Find Out” and actually go and find out what it is so I looked up UART and learn a bit.
Apparently it is protocol which is a standardize method of communication between two systems. In this case, the flight controller and the camera. UART stands for Universal Asynchronous Receiver/Transmitter. The asynchronous means that the two systems that have to communicate don’t have to have the same clock timing.
The two wires are RX on one to go to the TX of another and vice versa. It seems like UART protocol is a bit of an older style of communication between machines but it’s cheap and easy so it can helpful.
I wonder what all information is being sent? I’m assuming it is mostly the battery voltage.