The WT-9003 GSM remote controller incorporates a professional industrial grade GSM engine that receives calls at its SIM number, as any other ordinary GSM phone. The system operates in the GSM module quad band 850/900/1800/1900Mhz. Just to give an example, if your SIM has a phone number 9228 9810, that is the number you have to call to switch on/ off electric devices such as Automatic Gate, Heater, Fridge, HVAC, pump, motor and a lot more.
The system has a memory where the designated numbers are stored with a maximum of up to 250 numbers. When the WT-9003 receives a call, it will check the calling number and validate it with the listed numbers. If the number is in the list then it will reject the call and open the gate, switch on the boiler, turn on the heater, power up the motor and etc. The system does not answer the call, it simply checks the caller ID. Your network must send the caller ID otherwise the WT-9003 remote control will not work.
Usually operators don\\\'t charge until you answer the call, so it won\\\'t cost you anything to open the gate with the WT-9003. Of course, an active SIM is needed for this to be possible. To store a number, you simply send an SMS, that starts with a password to the WT-9003 GSM controller, indicating the phone number to enable its position in the list. Numbers are stored in the system\\\'s memory and not on the SIM. This prevents someone from removing the SIM to copy all the numbers into a mobile phone. Only the one who knows the password can insert or delete enabled phone numbers.