A circuit board for use in a modular electrical connector. Signal pathways is provided on a first surface. First ground pathways is provided on the first surface adjacent at least one of the signal pathways. Second ground pathways are provided on a second surface in line with the signal pathways. Vias extend from the first ground pathways through the circuit board to the second ground pathways, thereby placing the first ground pathways in electrical engagement with the second ground pathways. The first ground pathways, the vias and the second ground pathways extend along multiple pairs of the signal pathways and form cavities around the multiple pairs of the signal pathways to provide electrical shielding for the multiple pairs of the signal pathways.