1, PSTN & GSM security alarm with LED display and keyboard 2,99 wireless and 2 wired 3,Voice prompt function 1, PSTN & GSM, Voice ... for each zone, peripheral zone sound alarm, silent alarm around the zone, internal zone audio alarm, silent alarm within the zone, 24-hour zones ... , field, and so on, wired telephone networks can not reach. GSM security alarm system with LED display and keyboard,, security ...