I'm having an unusual issue with some of my FXO ports at one location.
When on a call through the PSTN (FXO to analog line) I can hear the other party fine as long as I don't make any noise. However, as soon as I start speaking the inbound audio is dropped for a moment and will continue to be unheard as long as I keep speaking.
However, as soon as I stop speaking the inbound audio is resumed.
It feels very much like a duplex problem. :-P
I've tested calling between sites (IP Phone to IP Phone over MPLS via the same router with the FXO ports) and that is fine. Also, IP Phone to IP Phone over the LAN is also fine.
It def. seems to be only related to calls to/from the FXO ports.
I've tried tuning the VAD parameters and completely disabling comfort noise. The issue doesn't seem entirely related to either of these but I thought I'd give it a shot anyways. No luck with either.
Thanks in advance!