The iPhone users insert second SIM cards in the smart home box, put them next to their home wireless routers, and download app from the app store and install it in the iPhone. After installed, the WiFi of the mobile phone is connected to the smart home box, then the registration button on app is clicked, the program automatically sets the smart home box to the home WiFi and completes the registration of the cloud server. Since then, users can use the app to call or answer the phone (using the same method as usual, and can also use the phone book of the iPhone), and the operations of sending and receiving SMS are the same.