An interface controller coupling the main body of an external electronic device to a host, and the electronic device using the interface controller and a control method for the external electronic controller are disclosed. The interface controller has a control unit and a non-volatile memory. The control unit is configured to transmit a termination-on signal to the host when link information retrieved from the main body has been written into the non-volatile memory. When the host issues a link information request in response to the termination-on signal, the control unit uses the link information stored in the non-volatile memory to respond to the link information request.