[asterisk-users] Ringing (180) no SDP to progress(183) with SDP transition => no audio.

Benoit Panizzon benoit.panizzon at imp.ch
Mon Nov 20 07:31:31 CST 2017

Dear List

I am testing various early audio scenarios with different voice IC's,
phones and pbxes.

In Switzerland, when you operate a value added number, you have to
announce the price of the call, usually in early audio, before the call
is established.

In 'dialplan' terms this would be:

exten => XX,1,Ringing
exten => XX,n,Wait(15)   
exten => XX,n,Progress
exten => XX,n,Playback(price-announce,noanswer)
exten => XX,n,Wait(5)
exten => XX,n,Answer 

I see the asterisk playing the early announcement audio in the rtp
stream. Some devices (arris EMTA) calling the asterisk also do play it
to the caller.


Most other devices I have tested just keep playing the locally generated
ringtone despite getting an 183 with SDP and the announcement is never
to be heard by the caller.

If I do to force inband ringback tone, this works with all devices I
have tested so far.

exten => XX,1,Progress
exten => XX,n,Ringing
exten => XX,n,Wait(15)   
exten => XX,n,Playback(price-announce,noanswer)
exten => XX,n,Wait(5)
exten => XX,n,Answer

Is anything wrong with the transition of ringing without SDP (to have
the local device generating ringback tone) and then start sending early
audio with 183?

-Benoît Panizzon-
I m p r o W a r e   A G    -    Leiter Commerce Kunden

Zurlindenstrasse 29             Tel  +41 61 826 93 00
CH-4133 Pratteln                Fax  +41 61 826 93 01
Schweiz                         Web  http://www.imp.ch

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