... advantages of the GSM Alarm System1)Two-way Voice communication or wiretap are available;2)LCD displays the entire setup menu ... SOS are available;4)Armed delay, alarm delay, siren work or not, more other functions are Programmable by user;5)Watchdog ... ;2)Supports armed, Partial armed(At House or Stay) or disarmed, SOS by remote control or mainframekeyboard;3)Supports armed, disarmed, inquiry mainframe ...