Home Alarm System 1,Touch keypad,Big LCD display 2,GSM+PSTN dual network 3,8 wired + 30 wireless zones 4,Work worldwide ... protocol(alarm information, status information, AC power off and recover, Low voltage, test) 8. Support wireless “ding-dong” doorbell function 9. Alarm ... working days More info,pls connect with us freely......... Wired/Wireless GSM+PSTN Dual-network Home Alarm System(L&L-816)