Electrical interconnection system and electrical connectors for the same

A connector comprising:

• first and second wafers, each wafer comprising:
• a housing comprising a mating edge configured to face a mating connector and orthogonal to a mounting edge configured to mount onto a board;
• a plurality of pairs of signal conductors and a plurality of ground conductors fixed at least partly within the housing and alternately arranged with one another along a transverse direction of the housing each signal conductor and each ground conductor in the pluralities of pairs of signal conductors and ground conductors comprising:
• a contact portion outside and at the mating edge of the housing for contacting a corresponding contact of a mating connector;
• a mounting portion outside and at the mounting edge of the housing for contacting a corresponding conductive trace on a board;
• and
• a connecting portion disposed within the housing and connecting the contact portion and the mounting portion, the connecting portion having opposing longitudinal edges extending from the mating edge to the mounting edge, the contact portions of each pair of signal conductors in one wafer facing the contact portion of a different corresponding ground conductor in the other wafer and when viewed from a side of the connector, the longitudinal edges of the contact portions of the pair of signal conductors are disposed between the longitudinal edges of the contact portion of the different corresponding ground conductor.