A phone-interface device receives a wireless signal from a control panel. The wireless signal encodes information regarding a system condition that has occurred in a facility. The phone-interface device communicates the system condition to a monitoring station. The phone-interface device receives its electrical power from the telephone line or from an energy storage device. In another aspect, the phone-interface device receives a provisional-alarm signal command from a control panel. The phone-interface device determines whether a disarm command has been received from the control panel. When a disarm command has not been received before expiration of a period of time, the phone-interface devices sends an alarm condition to a monitoring station.