An electrical connector includes: a plastic seat; a tongue; and two rows of terminals; characterized in that a front section of the tongue is a thinner plate body, top and bottom surfaces of the thinner plate body are two front-section surfaces, a rear section of the tongue is a thicker plate body, top and bottom surfaces of the thicker plate body are two rear-section surfaces, the rear-section surface of one of the top and bottom surfaces of the tongue projects more than the entire front-section surface of the corresponding one of the top and bottom surfaces of the tongue by a height so that a step is formed between the rear-section and front-section surfaces of each of the top and bottom surfaces of the tongue. A combination of the bidirectional duplex electrical connector and a docking electrical connector is also provided.