"Hey, let me interrupt you, Mr. Wang, as far as I know, there are three methods of mobile phone monitoring. Software implantation. By implanting specific software into mobile operating system, the one you just mentioned put the monitor in the cell phone battery is almost the same as this. But it's simpler for you to put the monitor in the cell phone battery, which is called hardware implantation and software implantation. It's still more difficult. Two are the hardware modifications just mentioned. The third is the interception of mobile phone signals. This method is to fix the target SIM card first. It is difficult to duplicate the SIM card in...