Because of inability to establish communication between Sena 10S and Interphone Sport intercoms, we have purchased 2 Midland BTT buttons to establish contact through our respective (sena and Interphone) intercoms via Bluetooth and the BTT buttons. All is working fine apart that my friend hears my voice, on his Interphone, on a reduced volume. I hear him loud and clear on my Sena, but we seem to be unable to somehow manipulate the volume so that he can hear me loud and clear as well. How can we resolve this.