In control and monitoring systems, there is a frquent demand for a simple fault indicator to be used as universally as possible. The wiring effort should be limited to a minimum; there is no space for additional controlling elements left. The devices of the series SSM are simple, very compact fault annunciator units for switchboard panel mounting. They provide LED displays with wide reading angle, integrated push buttons for lamptest and acknowledgement of lamps and horn as well as relay contacts for collective reports and horn triggering. Depending on the annunciator variant, the supply and signal voltage can range up to 250 V AC/DC. The wiring is done by pluggable terminals and the description of the LEDs can be done by slide-in labelling strips.