A machine case includes a bottom cover and a top cover with a connection port, encloses a printed circuit board therein. An internal flat cable is equipped with a first connector at one end thereof and mounted upon a center region of the printed circuit board, and a second connector at another end thereof and disposed in the connection ports without electrically connecting to the printed circuit board. The second connector includes a plurality of contacts integrally formed within an insulator via insert-molding. A cable connector assembly includes an insulative housing having a mating port adapted to be mated with the connection port. A printed circuit board is embedded within the housing and forms mating pads on two opposite surfaces in a reversely symmetrical manner so as to have the two corresponding mating pads on two opposite surfaces in the diagonal direction share the same circuits.