GSM Door Gate Opener Access Alarm System Remote On/Off Switch Free Call SMS Command    This GSM door opener has the function of remote switch. It can be operated from anywhere by authorized telephone call free of charge. There is no distance limit and it is very convenient.   Features:   850/900/1800/1900MHz four-band, can work in the global GSM network.   No telephone charges. When the GSM relay switch receives the call from the authorized number, the first "ring tone" is switched on or off.   Security. Use caller ID for identification, unknown callers will be ignored.   Add or delete users through SMS text commands.   There is no need to provide remote controls or keys for different users.   Up to 200 authorized telephone numbers can be configured within a specified time.   Relay action confirms the return message to the host or authorized call in the number. This function can be edited by the user.   The switching time of the relay is programmable.   Multiple applications, suitable for doors, pillars, fences, garage doors, shutters and doors or machines.   Specifications:   Model: RTU5024   GSM Frequency: 850/900/1800/1900MHz   Digital Output: NC/Dry Contact, 3A/240VAC   DC power supply: 9-15VDC/2A   Power consumption: 12V input maximum 50mA/average 25mA   SIM Card: Standard SIM Card   Antenna: 50 SMA Antenna Interface   Temperature range: - 20 ~ + 60 degree C   Humidity range: 90% relative humidity   Size: approx. 8.2*7.6*2.7cm/3.2*3.0*1.1in   Packing weight: 258g/9.1oz   Package list:   1 * GSM Door Opener   1 * User Manual