I am using osmo-nitb + osmo-sip-connector and nanoBTS to establish a per to peer call. I am using:

osmocom-nitb                    0.15.1.20161024 

osmo-sip-connector              1.20161024

While in call, I hear an annoying background noise while not talking. The noise disappears when someone speaks.

Any idea what might be causing this and how this can be fixed?

Thanks,

Stefan