I am using Xbee s1 , with SparkFun XBee Explorer Regulated,
I tested the peer to peer communication between two Xbees , mounted on usb explorer board, and they work just fine tx and rx both way.
then I tested one with 3,3 v i\o fdti cable connected to the xbee on the regulated board, and it works just fine (communicate with the one on the usb explorer board)
then I connected the ftdi directly to the pixhawk uart , and tested that I get data from it. ( again , works just fine)
but when I switch between the ftdi cable to the xbee on the regulated board, it sends nothing !!!
I was able to verify that the pixhawk do revive the data coming from the Xbee on the usb explorer board.
so what can be the problem???