Some Operator notification missing

Dear all

We are trying to reproduce a call so that Operator will send us a (error) audio notification. In this case we try to dial Unallocated Number and as the result we got ‘disconnect code 1’
The problem is; we are integrating QuintumDX with Asterisk which is in this situation Asterisk did not bridge the audio notification to SIP User Agent because there is no ‘early media indication (183/Session Progress) message’ received after INVITE issued by asterisk.

If I may refer to Dialogic device on below link, it will send 183/Session Progress after the receive CALL_PRECEEDING message from ISDN interface. … sip183.htm
(Example 1 - Receiving ISDN Progress after CALL PROCEEDING)

Based on the QuintumDX log attached on previous mail, after CALL_PROCEEDING_IND received from ISDN there is no 183/Session Progress message sent to Asterisk. Because of this situation, asterisk will never process the early media RTP to SIP User Agent.

Our question is ‘why for failed call the SIP User Agent unable to hear the audio notification from Operator?’
In this case we need the voice notification passed to SIP User Agent as the information is very important for them.

Would you kindly check and advise as to the cause of this.

Diagram System
{SIP User Agents}<—SIP----> {Asterisk IP-PBX} <—SIP----> {Quintum DX} <— E1 ----> {GSM Media GW} <—GSM Network—> {Customer Mobile/PSTN}

We are using asterisk

If the Quintum isn’t sending 183, you need to fix the Quintum.

However note that recent versions of Asterisk will not pass early media on SIP unless the Progress application is called explicitly. My guess is that this is because early media won’t normally be honoured on an incoming PSTN leg, as it would allow the making of un-billed receive only calls.