h6. [[SoundControl]] h6(. » Categories Current versions of SoundControl define the following category numbers. Positive numbers are used to identify inputs, while negative numbers identify outputs. |_<^. Input Categories |_<^. | |<^. 0 |<^. System audio - the sound produced by the OS | |<^. 1 |<^. Microphone | |<^. 2 |<^. Line in | |<^. 3 |<^. Aux in, e.g. CD audio | |_<^. Output Categories |_<^. | |<^. -1 |<^. Integrated speaker | |<^. -2 |<^. Headphones | |<^. -3 |<^. Line out | |<^. -4 |<^. Aux out |