Abstract: A system for providing the suppression of voltage transients and other electromagnetic interference with positive indication of the operational status of the system. More particularly, a transient suppression circuit is utilized that suppresses and dissipates electromagnetic interference and transient energies that might be present; furthermore, there are detection and indicator circuits provided indicating to the user (1) whether or not each circuit is operative and functioning as it should, and (2) whether indeed transients are present in the system. A central concept of the system provides for transient detection and suppression capability, that detects transient activity occurring at voltage levels greater than the suppression threshhold established by the transient suppression circuit. The system or device can be used as an insertion device directly in the line, or can be disposed in shunt across the power lines.