When I said headset, I meant headphones, i.e., earbuds, so there is no mic other than the one on my phone. That mic should still work when I have earbuds plugged in during a phone call, but it doesn't.
My Nokia Lumia 900 has a number of audio problems I believe are all related:
1. The ear speaker does not work during phone calls. The mic does not work unless the phone is in speaker mode. In speaker mode, the phone functions as it should (I can both transmit and receive voice). As soon as...