[ibiwan:~] jkent% ioreg -l -w 0 | grep IOAudioSelectorControlAvailableSelections 
    | |   |   |     | |   "IOAudioSelectorControlAvailableSelections" = ({"IOAudioSelectorControlSelectionValue"=1769173099,"IOAudioSelectorControlSelectionDescriptionKey"="IntSpeakers"},{"IOAudioSelectorControlSelectionValue"=1751412846,"IOAudioSelectorControlSelectionDescriptionKey"="Headphones"})
    | |   |   |     | |   "IOAudioSelectorControlAvailableSelections" = ({"IOAudioSelectorControlSelectionValue"=1768778083,"IOAudioSelectorControlSelectionDescriptionKey"="InternalMic"})