OK. I've scoured the www for this and so far I've learned that it is buzz (some kind of sound out). Why? What is the buzz sound for? The user manual leaves a lot to be desired. I also learned that one unfortunate owner had fried his board because he plugged a power supply to it. So, does it matter if I don't plug in that 2-pin dongle? Is it a gimmick?
only usefull part of the buzzer is the low voltage lipo alarm, which is kinda usefull.
And it beeps to let you know when you have armed or disarmed the board, which is also pretty useful, especially if the KK2 is enclosed somehow.
As above however you need to do some soldering to the kk2 board and then adjust some settings to make it work just search for kk2 voltage alarm setup on YouTube there is a great vid by dhdsracer
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