An electronic device is provided. The electronic device includes an earphone interface including a plug housing into which an earphone plug is inserted comprising contact points that contact electrode terminals of the earphone plug and protrusions connected to the contact points, and a substrate having signal lines coupled to the protrusions arranged in the plug housing to transmit signals to the electrode terminals of the earphone plug or receive signals from a specific electrode terminal. The substrate includes a ground line connected to a ground terminal of the earphone plug and a coupler that couples a wireless signal that flows through the ground line.