✅【Security】Use the caller ID to identify and ignore unknown callers. Add or remove users with the SMS Text command. There is no need to provide remote controls or buttons for different users.
💵【No call charges】the GSM relay switch answers the call from the authorized number and then performs an on/off operation on the first "ringing".
⚙️【The metal casing】and system are safely isolated, especially suitable for industrial control applications. Small size and support for wall mounting.
🤟【Multiple Applications】Suitable for doors, elevators, garages, car parks, resorts, control rooms, warehouses, unsupervised machine rooms of the group type, such as telecom operators, on-site lighting subframes, base stations on site, traffic controllers and distribution of electrical system and field cabinet.
🤳【With a remote on/off switch】for authorized calls for free calls, which can be operated from anywhere without distance restrictions. 850/900/1800/1900MHz quad band, can be used in the global GSM network.just support standard 2G SIM card