LINE IN ONLY -
Functions with headset ON audio passes through to the headset
Transmitter must be set to AUX for source
LINE OUT ONLY -
Only Functions with headset OFF, USB passes through to line out
Transmitter must be set to PC
LINE IN WITH LINE OUT -
Only functions with headset OFF, audio passes from USB through to Line OUT
LINE IN WILL NOT TRANSFER. (Line in only works in AUX mode and Line out only uses USB from PC source.)