SIP Response Code 404 instead of 503


We are running FreePBX 2.9 on top of Asterisk 1.6.2 and have an interesting issue with SIP response codes.

when we receive SIP 404 Not Found from our SIP provider Asterisk is returning 503 Service Unavailable to the handsets. From the research I have done this is because congestion is being called to hang up the trunk and the cause code is not being set.

Is it possible to change something in FreePBX to make the SIP response code be past through to the handset so it can display the correct message?



This issue has been resolved by using a custom macro-outisbusy override to detect the outgoing cause code and repeat it back out as part of the hangup of the calling channel.