1、The GSM‑AUTO 4G version is a wireless remote switch that can be connected to a 4G mobile phone network for control. By purchasing a SIM card (not includ) and a pay‑as‑you‑use (PAYG) plan from a local wireless provider, you can connect to a 4G or 3G or GSM cellular network. After installing the SIM card(not includ) into the SIM card (not includ) holder on the top of the GSM‑AUTO 4G module, it will have its own unique phone number. 2、Activate the machine by typing in its mobile phone number. The unit cannot answer voice calls, but when a call is sensed, its logic will activate one or two output relays in a pre‑programmed sequence. Since the device does not answer the call, the activation of the relay will not incur any call charges to the PAYG plan or the caller. 3、Each relay can be activated by sending an SMS text message to the phone number of the device. Similarly, the unit is programmed by sending specific SMS text commands. The GSM‑AUTO 4G unit controls 2 independent switches. Therefore, you can control 2 separate devices from one device. An example is in the aircraft hangar, turn on the battery charger and engine preheater in turn to prepare the aircraft for flight. 4、4G design, can work anywhere in the world through 4G, 3G and GSM Net. The secure caller ID allows to control the access of up to 100 authorized users. The user's phone number is added to the white list, and only the numbers in the white list can be used Activate GSM-AUTO, you can use text to add and delete user messages as needed. No call charges will be incurred when calling the device, it will recognize the authorized phone number and reject the call without answering. 5、GSM‑AUTO has two independent relays. They have normally open and normally closed contacts. They can be programmed to open between 1 second and 18 hours. In addition, the delay time between relay 1 and 2 switching can be set. By sending SMS to GSM‑AUTO, once programmed, you only need to call the unit to activate the programmed relay operation. 6、By sending a text message command to the device, you can temporarily cancel the programmed operation and open the relay for up to 18 hours. When the relay is open, it will return a confirmation text, and when the relay is closed, it will return another confirmation text.The relay can be permanently turned on or off by sending GSM‑AUTO. Return to confirm the SMS again. When the 24‑hour timer is enabled, the caller ID and priority functions will be disabled. 7、The onboard battery can be used for power failure alarm (battery not included). Applications include vacation homes, lighting, engine preheaters, aircraft engine heaters, irrigation systems, water well pumps, pumping stations, remote control of the heating of cabin heaters, resetting of remote servers, arming and disarming security systems, doors Access control and garage door. Item Type: Remote Controller Material: ABS Operating Voltage: DC 12V Operating Current: Max. 450mA, typical 60mA Relay Contact: Double relay output channel: normally open and normally closed Alarm Input: 1 Channel alarm output Operating Temperature: -20℃ - 55℃ Waterproof Grade: IP65 1 x Double Channel Remote Controller 1 x Antenna 1 x USB Cable 1 x USB Programming 1 x Manual