a socket connector includes a socket base , a socket cover slidable mounted on the socket base , a base plate received in a recessed area defined in the socket base , and an eccentric cam member rotatable engaging with the socket cover , the socket base and the base plate so as to actuate the socket cover to move with respective to the socket base between an open position and a closed position . keying means is provided between the base plate and the recessed area so as to prevent the base plate from mismating with the socket base .