Thanks to sarond and acejavelin, I recently got my SIP trunks connecting to my provider. We're in the final stages of commissioning this service, and we have an issue when a call is made from the site, or into the site, only the incoming voice from external is being heard; we can't hear outside at all.
I've confirmed the gateway on the phone is correct, and the provider is blaming the SIP configuration as he says there is only one codec being offered, G.729, and none of the G711 codecs are being offered.
Attached are two images he shows from his traces, one has just the G.729 and the other shows nothing - this was when I filtered out the G.729 so it just has G.711u and G.711a.
I've tried this with 'Renegotiate SDP To Enforce Symmetric Codec' turned both on and off and it doesn't show anything different.
The strange thing here is that when I put the system into night mode and call the voicemail system, I can hear it without a problem.
I have gone through the configuration guide that the provider gave me (as well as the copy sarond sent through, thanks!) and the settings all match. I am out of ideas.
Currently, I have:
Renegotiate SDP To Enforce Symmetric Codec turned off
Restrict Audio Codec - No Restriction
Codecs filtered are all except G.729