Progress

Synopsis

Indicate progress

Description

Progress()

This application will request that in-band progress information be provided to the calling channel. This is also known as "early audio" and "early B3" (for example: see Dial option /b in chan_capi-cm). Note that early audio also needs to supported by your carrier in order to work for the caller.
Typically used in conjunction with Playback and its 'noanswer' option (previously 'n' option).

On an unanswered SIP channel this will send a "183 Session Progress" to the endpoint.

Starting with Asterisk 1.6.2: SIP no longer sends the 183 progress message for early media by default. Applications requiring early media should use the progress() dialplan app to generate the progress message.

Example

exten => 500,1,Progress()
exten => 500,n,Wait(1)
exten => 500,n,Playback(WeAreClosedGoAway,noanswer)
exten => 500,n,Hangup()

ISDN incoming call - inband info and announcements BEFORE ANSWER

Question: Is there a way to force Asterisk to send DSS1 PROGRESS message to PSTN with indicator: "Inband information now available", before call is established (even before ALERTING phase)? I also think that this indicator can be contained in CALL PROCEEDING message.

My idea is to play not billed welcome message on Asterisk system. Just now there is incoming SETUP, Asterisk replies with CALL PROCEEDING (without indicator I presume - but I can think only from Asterisk trace, no ISDN tester available at the moment). In ideal case there should be send PROGRESS or CALL PROCEEDING message with that indicator.

How to setup this (for PRI and junghanns.net BRI)?

Answer: Use the Progress() application in your dialplan before you Answer() the line. Use the Background() application with the 'n' flag or the Playback() application with the 'noanswer' flag to play your announcement (so the line is not Answer()'d automatically for you).

See also

• Digium Wiki on Early Media
• Asterisk sip progressinband
• Asterisk sip prematuremedia
• Asterisk cmd proceeding as in Asterisk 1.6
• Asterisk cmd Answer
• Asterisk cmd Ringing
• Asterisk cmd Playtones
• Asterisk variable PRI_CAUSE: Set an ISDN cause code

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