Socket connector and plug connector

A socket connector is provided with an inserting hole for accommodating a plug connector. The socket connector comprises a socket body and a plurality of socket terminals accommodated in the socket body. Each socket terminal comprises a contact portion extended into the inserting hole and a welding portion extended out of the socket body. The contact portions of the plurality of socket terminals are aligned into a row along the right-left direction. The plurality of socket terminals comprise a pair of ultra high speed differential signal receiving terminals, a pair of ultra high speed differential signal sending terminals, a second grounding terminal positioned between the ultra high speed differential signal receiving terminals and the ultra high speed differential signal sending terminals, and a power supply terminal adjacent to the ultra high speed differential signal receiving terminals or the ultra high speed differential signal sending terminals. The socket terminals are small in number and simple in st