US Patent 9825628 Electronic device and operation method thereof

An electronic device includes a transmission interface and a control circuit. The transmission interface includes a signal reference contact and a signal transmission contact. The control circuit is electrically coupled between the signal reference contact and a ground layer, in which the control circuit is configured to selectively conduct the signal reference contact and the ground layer, and when the signal reference contact and the ground layer are conducted, the signal transmission contact is configured to transmit a first signal, and when the signal reference contact the ground layer are not conducted, the signal reference contact is configured to transmit a second signal. A transmission frequency of the second signal is less than a transmission frequency of the first signal.