Thanks for reply it was a controller mis match the Phantom 4 Pro uses a GL 300F and the Phantom 4 standard uses a GL 300C. The GL 300C i was trying on the Phantom 4 Pro is un compatible, also the GL 300C will not work with DJI assistant 2 for Phantom.Might help to know which model drone you are trying to connect to. Firmware needs to match.