I have two OBi110s configured as FXO trunks into an IP PBX and I can make and receive calls without much ado.
However, I'm experiencing a problem with near end incoming audio. Whenever the far end begins to talk, the volume is initially very low but quickly comes back to normal (around a second). This causes the beginning of far-end sentences to be cut off, which is annoying at best. Once they're talking audio quality is fine. The problem occurs only when the near end stops talking and the far end starts talking. There is no problem in the other direction. The problem occurs on every call, both incoming and outgoing.
To me it seems like some sort of overzealous echo cancellation, but I'm not totally sure.
Also, for what it's worth, I had a bit of trouble sending DTMF at first. To solve this increased the interdigit spacing and the problem went away. I don't know if the two are related.
I'd welcome any input. Thanks.