an insulative housing comprising a mounting surface for mounting on the printed circuit board, a front face and an opposite rear face, and at least one receiving space extending from the rear face toward the front face; and

at least one terminal unit assembled to the insulative housing and comprising a plurality of signal contacts received in the housing, a first switch contact comprising a first base portion retained in the housing, a first spring arm extending from the first base portion, and an insulative separator disposed about the first spring arm and extending into the receiving space, and a second switch contact comprising a second base portion retained in the housing and a second arm extending from the second base portion, wherein when a mating plug inserts into the receiving space, the separator is engaged by the mating plug to move in roughly a radial direction perpendicular to a mating axial direction, and thus drive the first switch contact to connect the second switch contact;

a cavity being formed in the front face of the housing;

a mating port defining a rear section received in said cavity, and a front circular section extending beyond the front face of the housing under a condition that one grounding contact defines a distal contacting end disnosed in the mating port around a joint portion of said rear section and said front section;

a metallic shield enclosing said housing and including a front wall covering the front face with a corresponding circular opening through which the front circular section extends;

the separator defining a position where said mating plug is engaged, said position being located in an innermost area of the receiving space and far away from said distal contacting end of the grounding contact.