I'm trying to use this with CF4 (on XP SP2) and can't get much help, especially from CF directly. The MT107A shows up fine under recording devices, but I let my SB External USB 5.1 sound card selected as the default for both playback and recording, and then in the CF settings, I would choose MT107A Wave-In for the bluetooth input device. Unfortunately, the person I am on the phone with cannot hear me at all. If I choose my SB External card for playback and the MT107A for recording, the person on the other end can hear me, but I can no longer change volume in CF. It just stops working and the volume is wherever it was last set. I've had this setup as a digital input for the microphone (USB connection), so I used the OUT2 (microphone out of the MT107A) into the Line-In of the SB External sound card, and set both playback/recording to SB External again. Now I can change volume and the person can hear me, but they have their own echo, which was the whole purpose of installing the MT107A.
I have no idea what is going on here, but I know others are using the MT107A, so I want to know what I am missing. The only thing I find strange is under the sound properties in the control panel, it always has "use only default devices" checked...and if I uncheck it, it will re-check itself when I re-open the properties.