Surge protection, consisting of plug-in protection and base element, with integrated status indication for an intrinsically safe 3-wire signal circuit. For high-frequency applications. Protection circuit only with gas arresters. For use in two-wire Ethernet systems with cable display (APL, 2-WISE) and in the fieldbus system (e.g. PROFIBUS PA) according to the intrinsically safe bus concept. Can be used in safety-oriented circuits up to SIL 3.