I am trying to install the iosd mini with pmu v2 into my phantom v1.2 and I wonder about these connections labled x1 x2 x3 on the Naza M device. When I opened it up there is a 3 wire connector leading to the main board from the x3 slot. There was the same set up in X2 that leads to the board that has the antenna. Now on the pmu there is a connector that says X3 and some other stuff that looks like voltage, can those be plugged into any of those 3 slots? Then there is the slot labled U still under the EXP main heading, what are the uses of that slot. I read the pmu manual and I start to get a headache so any help or pointers on where to look is appreciated.