An electrical connector comprising a housing having a mating face and a mounting face, a plurality of signal contacts (120, 122) held by the housing, the signal contacts (120, 122) being arranged in differential pairs to form signal contact pairs, each of the signal contacts (120, 122) having a body (154, 181), a signal contact pin (170, 182) extending from one end of the body (154, 181) along a pin axis, and a signal contact tail (180, 183) extending from an opposite end of the body (154, 181), the body (154, 181) and the signal contact tail (180, 183) extending along a contact plane (155, 212), the signal contact pin (120, 122) including a transition section that off-sets the signal contact pin (170, 182) out of the contact plane (155, 212) in a lateral direction, and ground contacts each having a ground contact body, a ground contact pin extending from one end of the ground contact body along a ground pin axis, and a ground contact tail extending from an opposite end of the ground contact body, wherein the ground contacts are associated with the signal contact pairs, and the ground contact pin and ground contact body of each ground contact lie along a ground contact plane, wherein the signal and ground contact pins (170, 182, 200) are arranged in a first pattern at the mating face and the signal and ground contact tails (180, 183, 208) are arranged in a second pattern at the mounting face, wherein the signal and ground contact pins (170, 182, 200) are arranged in columns along column axes, and adjacent columns are aligned with one another such that the signal and ground contact pins (170, 182, 200) are arranged in rows along row axes, wherein the signal contact tails (180, 183) of each signal contact pair are aligned along a respective tail axis (262, 358), characterized in that: the tail axis of each signal contact pair having signal contact pins arranged in an odd numbered column is orthogonal to the tail axis of each signal contact pair having signal contact pins arranged in an even numbered column, and in that: the signal contacts (120, 122) of each signal contact pair and their associated ground contact that have signal and ground contact pins (170, 182, 200) arranged in an odd numbered column, each have their signal and ground contact tail (180, 183, 208) disposed in the contact plane (155, 185, 212) and off-set with respect to the pin axis (172, 202) and the row axis of the signal or ground contact pins (170, 182, 200), the offset being in a first transverse direction that is perpendicular to the lateral direction, the signal contacts (120, 122) of each signal contact pair and their associated ground contact that have signal and ground contact pins (170, 182, 200) arranged in an even numbered colunm, each have their signal and ground contact tail (180, 183, 208) disposed in the contact plane (155,185,212) and offset with respect to the pin axis (172, 202) and the row axis of the signal or ground contact pins (170, 182, 200), the offset being in a second transverse direction that is perpendicular to the lateral direction and opposite to the first transverse direction. the tail axis of each signal contact pair having signal contact pins arranged in an odd numbered column is orthogonal to the tail axis of each signal contact pair having signal contact pins arranged in an even numbered column, and in that: the signal contacts (120, 122) of each signal contact pair and their associated ground contact that have signal and ground contact pins (170, 182, 200) arranged in an odd numbered column, each have their signal and ground contact tail (180, 183, 208) disposed in the contact plane (155, 185, 212) and off-set with respect to the pin axis (172, 202) and the row axis of the signal or ground contact pins (170, 182, 200), the offset being in a first transverse direction that is perpendicular to the lateral direction, the signal contacts (120, 122) of each signal contact pair and their associated ground contact that have signal and ground contact pins (170, 182, 200) arranged in an even numbered colunm, each have their signal and ground contact tail (180, 183, 208) disposed in the contact plane (155,185,212) and offset with respect to the pin axis (172, 202) and the row axis of the signal or ground contact pins (170, 182, 200), the offset being in a second transverse direction that is perpendicular to the lateral direction and opposite to the first transverse direction.