When a 3.5mm plug is inserted into the TB, the phone's mic is muted (no way to unmute except unplugging the 3.5mm plug). You can hear the incoming call through the car's speakers, but they can't hear you. On my '09 Equinox (and most cars prior to '11) BT streaming only supports phone calls, not streaming music. Even when the BT is streaming your phone call to your car radio, if you have something plugged into the 3.5mm port, the phone's mic is muted and they can't hear you.