Your security system’s host receives signals from sensors installed. This is done through radio frequency of 315MHz or 433MHz. WIFI is not needed at the moment.
When a signal is received, subject to the command that you set through your smartphone, it will either; ignore (if ‘disarmed’), ring the bell, ‘ding-dong’ (if ‘doorbell’ function is selected) or it will trigger the siren and send SMS / push notification.
Your security system host is connected to the Internet using WIFI (primary) or GPRS / 3G (secondary). While online, the host will send push notification. It’s free. App is used to change setting of your security system.
If the data comm not available (for example; ‘host offline’- data of the host fails, or no data available to your smart phone), SMS is used to connect a host directly to your phone. This enable you to ‘arm’ or ‘disarm’ the system. Smartphone application is not necessary. In this situation, any mobile phone can be used.
The last way to activate the ‘arm’ or ‘disarm’ is a phone call to the host using passwords and numeric key input. Any phone can be used for this purpose.