A cable includes a transmission cord having two connecting terminals formed on two opposite ends thereof, two connectors respectively mounted on the two connecting terminals of the transmission cord, two end caps mounted on the transmission cord and respectively connected with the two connectors, and at least one demagnetizing layer mounted on the two connectors and received in the two end caps. The transmission cord includes a conducting wire, an insulating layer wrapped around the conducting wire to insulate the conducting wire, and a protective layer wrapped around an outer face of the transmission cord. The at least one demagnetizing layer is made of graphene to prevent the electromagnetic waves of the ambient environment from interfering with the signal transmission of the transmission cord.