OCS / Exchange UM - Mitel 3300 external call early connection RRS feed

  • Question

  • We've got our OCS and Mitel 3300 implementation up and running pretty nicely.    Mixture of EV and Mitel/RCC users with Exchange UM providing voicemail for both.   The 3300 handles PSTN connectivity and both Exchange and OCS are connected to it via sip trunks. 

    One nagging issue I'm having, however, involves the the simultaneous ring feature for OCS EV users.   If the users sets simultaneous ring to go to any internal extension (either ocs or mitel 3300 based), simultaneous ring works as expected.  If, however, they forward it to an external pstn number, the toast appears on their system, but immediatley switches to say "<external number> answered".    This happens while the external phone is still ringing (it hasn't been answered).  
    If the external user does pick up the call, it connects and proceeds normally, but this pretty much defeats the purpose of simultaneous ring. 

    I also see a similar behaviour in Exchange if I use the play-on-phone forwarded to an external number.   The play-on-phone box switches to "connected" as soon as the destination number starts to ring.    If I then answer the external phone, the call connects but Exchange will already be into reading the voicemail (presumably it starts reading when it sees the call connected).

    Given that both exchange and ocs are doing the same thing, I think it has to be something in the config of the sip trunks or the 3300's internal options, and it seems to be related to how things are forwarded by the 3300 externally, but I haven't been able to figure it out.   Has anyone run across this type of thing before?

    Thanks in advance for any replies
    Friday, January 22, 2010 10:54 PM


  • We found the solution to this in case anyone else runs into it.

    After the ticket being open for 3 days, mitel finally came back with the following:

    In the Class of Service Option Assignment for the OCS / exchange sip trunks, you need to set "Suppress Simulated CCM (Call Connect Message) after ISDN Progress"  to Yes.   

    After setting this option, exchange and ocs can dial out correctly.


    • Marked as answer by rsweezie Friday, January 29, 2010 11:31 AM
    Friday, January 29, 2010 11:31 AM