a) Why module can not communicate properly?
1) The power supply is connected incorrectly and the module is not working properly;
2) 2) Check whether the frequency band of each module and other RF parameters are consistent;
3) 3) Is the module d1) Power supply ripple is 2) The antenna types do not match, or not properly ins3) The surrounding environment is harsh, strong interference s4) Surrounding co-channel interferenc
