1, PSTN security alarm with LED display and keyboard 2,99 wireless and 2 wired 3,Voice prompt function 1, PSTN Voice ... registration network.3, equipped with integrated color LED function display, date, clock, display and keyboard set, the query. 4, the host 5 ... warehouse, field, and so on, wired telephone networks can not reach. PSTN security alarm system with LED display and keyboard, security alarm ...