Seems to me that I'm not configuring something correctly or hitting some bug.
I have a T.38 incapable provider that will respond with SIP 488 back.
If I leave T.38-passtrough and get 488 back, RTP stops and call is dropped. So I was trying to set up correct transcoding.
PBX sends txfax (file.tiff) to PROXY which forwards call to PROVIDER (g.711).
PBX sends T.38 re-Invite, PROXY responds with 200 OK but then I have 2 scenarios: either passtrough T.38 which will invoke 488 and dropped call or I tried
sip_execute_on_image=t38_gateway peer nocng"
but this doesn't send anything to PROVIDER but also call is dropped after BYE and 486 message.
Case that I'm hitting is similar to this:
"If you want to transcode t.38 on leg a to audio on leg B when leg a invites t.38, but refuse all t.38 offers from leg b "
but to refuse t.38 invites from lag a.
The other way around, call from PROVIDER to PBX over PROXY is easely transcoded with
sip_execute_on_image=t38_gateway self nocng"
on the PROXY side.
Is it normal behaviour that After failed t.38 negotiation or 488 message, fax call doesn't fall back to previous codec or t.30?
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