I swear i answered this exact same question in the last couple weeks in a different thread.

On Aug 25, 2014, at 1:32 AM, Avi Marcus <avi@avimarcus.net> wrote:

OK... I set ringback variable on the A leg, but that doesn't seem to start until the 180... as makes sense.
Maybe I wasn't clear: Is there a way I can play something until the 180/183 response?

Thanks,
-Avi

On Sun, Aug 24, 2014 at 9:05 PM, Anthony Minessale <anthony.minessale@gmail.com> wrote:

If you set the "ringback" variable on the inbound leg, that is what will happen as long as you dont set ignore early media.

On Aug 24, 2014 5:37 AM, "Avi Marcus" <avi@avimarcus.net> wrote:
Is there a way to play a ringback... until the actual ring starts?

The intention is a "placeholder" on my calling card until the actual ring starts.
Sometimes mobiles take quite a while to start ringings, and sometimes numbers keep timing out - I'd like to give an audio-feedback that the process is indeed working.
I know I can easily start the ringing right away, but I don't want to do that because it gives the impression that the call is actually going through, which may not be the case.

I don't see anything that immediately apparent on the wiki - any suggestions?

Thanks,
-Avi