A modular connector assembly comprises a main shell assembly having an aperture therethrough defining a inside surface. An electrical circuit assembly is disposed in the main shell aperture and includes a filter module and a transient suppression module each in electrical engagement with a plurality of electrical terminals. The filter and transient suppression module each define a conductive subassembly shell and each include grounding means disposed to engage the inside surface of the aperture in the main shell assembly in electrical grounding contact. Both the filter and transient suppression modules each define a first and second guide means disposed to engage first and second aligning means of the main shell member permitting facile precision assembly.