1. Multiple mobile phones are connected to the same WiFi service bell at the same time, or multiple WiFi service bells are connected to the same mobile phone. 2. Suitable for hospitals, nursing homes, nursing centers and other places that require dedicated care; through the call notification of the WiFi service bell, professional caregivers can arrive at the person being cared for as soon as possible. 3. As the population structure begins to age, in order to prevent accidents and misfortunes cau