... & Features of the GSM Alarm System :1.Touch keypad; Big LCD displays, NO EXTERNAL GSM ANTENNA ON THE PANEL2. GSM network ... , 1 extra SMS alam number to receive alarm informatio like LOW-VOLTAGE, ARM/DISARM status etc6.Alarm SMS include alarm zone ... protocol(alarm information, status information, AC power off and recover, Low voltage, test)8.Support wireless “ding-dong” doorbell , user can ...