TCL s720t USB Debugging how to open? Where is the USB debugging of TCL?

1 we found in Tcl s720t "Settings" click to enter, as shown in the figure, and then in the settings list to find "about the phone" below the "version number" We use our fingers to connect click 4 times, as shown in the picture

2 waiting for the prompt to open the USB success, we go back to the phone's "settings", you will find a miracle happened, see the "Developer option", into the "developer option" can be opened, then you want to do what you do.

Well, it turns out that the mobile phone intelligent system used by TCL is upgraded to a newer version, because as long as the version after the Android 4.0 USB debugging defaults are not turned on, if you want to open it must be operated by the factory, the method above also introduced in this hope that the students will help you.