An interface control circuit complying with an interface specification includes: an interface signal transceiver circuit and a protection circuit. The interface signal transceiver circuit is coupled to a first interface connection pin and a second interface connection pin of a first interface connector circuit. The interface signal transceiver circuit is for transmitting and/or receiving an interface signal according to the interface specification. When the interface signal transceiver circuit operates under a first state, the protection circuit determines whether a foreign object exists between the first interface connection pin and the second interface connection pin according to a voltage change or a current change at the second interface connection pin. Under the first state, the interface signal transceiver circuit generates a pull-up signal and a pull-down signal which are toggled with each other at the first interface connection pin.