A communications jack includes: a jack frame having a plug aperture; a plurality of contact wires, the contact wires having free ends that extend into the plug aperture, the free ends of the contact wires being arranged serially in side-by-side relationship; a plurality of insulation displacement connectors; a dielectric mounting substrate, the mounting substrate including a plurality of mounting locations for contact wires and a plurality of mounting locations for insulation displacement connectors; and a plurality of conductors mounted on the substrate, each of the conductors extending, defining a path, and establishing electrical connection between a contact wire mounting location and an insulation displacement connector mounting location. At least one of the conductors includes two self-coupling sections that are immediately adjacent to each other and that have identical instantaneous current direction such that the sections self-couple and cause a localized increase in inductance.