Enerna IoTech 4G LTE GSM gate automation door entrance relay switch RTU5024 with more powerful function. It support up to 999 authorized telephone numbers for SMS free call and Android/iOS app remote controlling. And it have two inputs which can connect alarm sensors for security protection.1. 4G LTE GSM gate automation door entrance relay switch is a very simple equipment, which can be used to authorize access control, control access control, remote equipment switching, parking system, etc. In fact, the device can be used where your system, machine and equipment need to be turned on or off, and can make calls from your mobile phone for free and protect your assets. 2. Simply dial the authorized user number to open or close the fence, door or machine. Without the call fee, the GSM access controller rejects the call authorization number and then performs the open / close operation. 3. In addition, the equipment has two digital inputs. When any input is triggered, it will start the alarm or turn on the indicator. At the same time, the equipment will send SMS alarm and notify the owner immediately. This is useful if you need a low-cost solution to protect your assets.