smoke detector with open source

smoke alarm with PSTN direct from Wanlin Fire Protection — 12-year factory experience, WL-Kit-4G 4G smart fire protection product certified CE/FCC/RoHS/REACH/ISO9001. Key specs: 4G LTE + WiFi + Zigbee Multi-Protocol Hub with 15 Sensors, 4G LTE + WiFi + Zigbee + SMS + Push + Phone Call + App + Voice + Cloud Platform. No monthly fees, 4G cellular backup, cloud···