What is this exactly? Is it somekind of noisegate where the background ambient noise is blocked? `Cause if it is, that´s really annoying. I was talking with my friend on the phone. I don´t know what phone he has, but I suspect his phone had this "feature". When he didn´t talk the line went always absolutely dead silent. I was wondering and asking him all the time "are you still there?". Totally frustrating!