An electrical connector includes an insulating housing and a plurality of contacts retained on a mating portion of the housing. The mating portion has a mating port with a geometric centre. The contacts are divided into an upper array and a lower array. Each array includes several first contacts and at least one pair of second contacts located on two sides of the first contacts, the first contacts of the upper array are centrally symmetric to the first contacts of the lower array relative to the geometric centre of the mating port. The new type of contacts arrangement can improve the quality of the signal transmission.