1. Emergency call system: (1) Fall Detection & Alert: The Bluetooth necklace worn by the elderly detects a fall (active call for help), and the system issues a fall alarm to notify the caregiver to take care of it. (2) SOS Alert: Press the necklace (active call for help) SOS button, the system sends a SOS alarm notice. 2. Indoor positioning system: (1) Event location system: When an event occurs, the system will detect the incident location and place it on the alarm list.