A connector assembly includes a main substrate (20) disposed in a substantially vertical orientation within a connector housing (10). Four conductor-holding halves (301, 303, 401, 403), laterally and longitudinally aligned with each other, are mounted onto opposite front and rear faces of the main substrate for forming a complete upper connector, and a complete lower connector. This arrangement of the upper and lower ports shares a common main substrate, and is optimal from space usage due to having full advantage of opposed face areas defined by the main substrate.