The GSM-CTL-4G is a wireless 3G / 4G / GSM remote control switch that connects to the cell phone network.
It has seven independent relay switches, and the NO. 1 Relay switch is activated by calling its cell phone number, it will reject the call without answering and switch on the device connected to it, then there are no call costs incurred when dialling the unit, it will recognise an authorised telephone number calling it and reject the call without answering.
It has other one relay independent relay switches which can be switched on or off by sending the GSM-CTL an SMS text message.

Specifications:Real-time & interactive control
Works with GSM phones
Relays operates almost every appliance
Relay memory after power failure
Optional password to keep the system at safety operating mode.
Remote Password change
Two operating mode optional ( remote setting with GSM phones)
One relay is woking with the phone calling, and others working with the SMS
Commands can added to GSM-phone number for ready made commands

 Support free control mode or Security Authorized number control mode 
 Quick & easy number programming with SMS or On Board Fast Teaching Button. 
 Can disable the SMS reply back to save the cost
 Support Customized command for easy understand
 Support the optional Wifi-plug for remote parameters program 
 Support device operation history LOG check

Applications:

Applications include the remote control of heating in holiday homes, lighting, engine pre-heaters, aviation engine heaters, irrigation systems, water well pumps, pumping stations, cabin heaters, resetting of remote servers, arming and disarming security systems, access control of gates and garage doors.