Built-in SIMCOM, double frequency GSM module (SIM300 or SIM340) 2. With color LCD show screen and keyboard on the host Built-in SIMCOM, double frequency GSM module (SIM300 or SIM340)2. With color LCD show screen and keyboard on the hostThe alarm system adopts SMS data transmission and voice platform of GSM network to send control command and receive alarm remotely. The system can be set delayed- ...