The SPCP433.300 smart power supply expander (PSU) extends the acre Intrusion system via X-BUS with a monitored 12 VDC local power source for battery management and connected security devices (e.g. expanders) and advanced door control functionality for 2 entry doors or 1 entry/exit door. The PSU comes in a tamper protected hinged metal housing with space for an optional 17 Ah battery and 3 expanders.