An interface circuit for use in an electronic device includes a switch module and a control module including signal receiving and transmitting pins. When a first audio terminal of the electronic device is electrically connected to a second audio terminal of another device, the control module controls the switch module to establish electrical connection between the signal receiving pin and the first audio terminal. The control module controls the switch module to establish electrical connection either between the signal transmitting pin and the first audio terminal for proceeding with a program update when updating information from the second audio terminal is received through the signal receiving pin or between an audio signal providing module of the electronic device and the first audio terminal when no updating information is received.