having done the move from FP3 to FP5 and used to do calls with Jabra headset attached, I bought the original Fairphone USB to 3.5 mm TRRS socket in order to use it with the FP5.
My issue now ist, that the mircophone signal level through this adapter is far too low and the other side of the call does not underständ a word.
I have not found a level matching dialoge as one can find i.e. in Windows OS.
Would he happy about any idea. The headset is working with my FP3, so it is not defective.
Ok, what I could find out on my own is, that it seems, the Fairphone USB to 3.5mm trrs adapter ist responsible for described behaviour. Using two different dedicated USB headsets lead to normal mirophone levels. If the adapter is not broken, I am sorry to say, this is poor quality from Fairphone.