The electric conversion stage according to the invention can be connected on one hand to intermediate terminals of a DC voltage electric bus, and on the other hand to output terminals. Some aspects of the present disclosure may improve the legacy tune-away operations at an access terminal. The method further draws a distribution map of the WIFI devices according to the coordinate value of each of the WIFI devices, and displays the distribution map indicating the location of each of the WIFI devices on a display screen of the electronic device.