The PK152 Annunciator Control Unit provides power and control circuits to operate Tek-CARENC150, NC200 and NC110 nurse call systems or the Tek-SAFE area of rescue assistance system. The PK152 contains the electronic circuitry necessary to detect the presence of normal and emergency calls, and to generate audible and visual control signals. It provides steady or intermittent voltages to operate visual signaling devices. The PK152 supports up to 1 amp of current load from field devices, and supports interconnection of a secondary power supply (PK800A) to increase the output current load to 3 amps. Protective circuitry has been incorporated to protect routine and emergency call commons from shorts.