An electrical connector (100) includes an insulative housing (1) having a base (11) and a tongue plate (12) protruding beyond the base (11); a set of contacts (2) having contacting portions (26) arranged in one row along one side of the tongue plate (12), the contacts (2) consisting of a first type of grounding contacts (G) and a second type of a set of pairs of differential contacts (24, 23, 22, 21), the differential contacts comprising a first pair of differential contacts (24) for bi-directionally transmitting data and a second pair of differential contacts (23) for unidirectionally transmitting data, in the contacting portions (26), the grounding contacts having at least two grounding contacts (G1, G2) arranged between the first pair of differential contacts (24) and the second pair of differential contacts (23); and a metal shell (3) covering the insulative housing (1) and having a receiving space (30) for the tongue plate (12) extending into.