IAX2 provider that passes audio on-hook?


From my own testing, I find that IAX2 passes audio when “on-hook” (that is, before the ANSWER message is sent). Unfortunately, all the software IAX clients I’ve tested so far have a hard-coded client-side ring that interfers with any audio being passed from the server, but that’s another matter.

Given that IAX2 is capable of passing audio before the channel is answered, are there any IAX2-PSTN gateway services that allow their subscribers to pass audio to DID callers without having to answer the call (e.g., to play error/no-service messages)?