An electronic device includes a connector for connection to an external device; a controller electrically connected to a first external device detection terminal of the connector to detect an electric state of the first external device detection terminal and to output a signal corresponding to the detected electric state; a processor having a first input terminal electrically connected to the controller, that is configured to receive the signal through the first input terminal, having a second input terminal electrically connected to a second external device detection terminal of the connector, and that is configured to detect an electric state of the second external device detection terminal; and an electronic component disposed between the second external device detection terminal and the processor such that an overvoltage is not entered into the processor through the second input terminal. Various example embodiments are available.