The Sentinel Area of Refuge System is designed to provide fully supervised, full duplex voice communication, between each Call Station (4800VS) and the Base Station(s) A-4800BS through the Main System (CM-4800S). An internal modem, connected to a telephone line (VoIP, POTS, or SIP) provides an automated-timed dial-out capability to a central monitoring location (not provided). For extra security and protection, Base Stations can be mounted in an enclosure (BB-48S). Enclosure comes as flush mount but can be semi-flush mounted with trim ring (BB-48TS).