Teknika 4 fault annunciators are digital units with front end lit by LED's. Applications are in monitoring fault conditions in any process, equipments etc. A potential free fault condition triggers a buzzer, trip contact and a contact for hooter if external hooter is desired. Also the corresponding window flashes, two changeover contacts trip to signal trip indication and an internal buzzer beeps to signal fault condition. When the acknowledge push button is pressed the flashing becomes steady, the buzzer stops and the hooter contact is released. Test checks all the windows.