An electronic device includes a transmission medium and first and second duplex electrical connection plugs. The first duplex electrical connection plug includes: an insulated seat; two terminal sets disposed in the insulated seat; and a metal housing covering the insulated seat and provided with a four-sided primary housing, wherein heights of two contact interface substrates of the second duplex electrical connection plug can be fit with the two spaces of the two connection surfaces of a tongue, and a connection slot of the first duplex electrical connection plug is fit with the tongue. The second duplex electrical connection plug includes: an insulated seat; a metal housing covering the insulated seat; and a fitting portion provided on one end of the insulated seat, wherein heights of two contact interface substrates of the second duplex electrical connection plug can be fit with two spaces of two connection surfaces of another tongue.