An audio signal adapter device detects whether a sequence of a microphone pin and a ground pin of an apparatus with an audio plug matches a detecting device into which the audio plug is inverted. The device includes a first interface having an audio signal receiving pin, a microphone pin and a ground pin, and a second interface having an audio signal output pin. An audio signal amplifying circuit is configured to amplify an audio signal received by the audio signal receiving pin and to output the amplified audio signal to the audio signal output pin. The audio signal received by the audio signal receiving pin flows to the microphone pin or ground pin via an impedance equivalent part of an audio signal amplifying circuit. The impedance circuit is coupled between the microphone pin and ground pin. An interface detecting system and an electronic signature token are also provided.