Lync and Trixbox noise supression issue RRS feed

  • Question

  • I have setup a MS Lync server that is working at taking calls.  My customer requested to add in Polycom 8030 wireless handsets.  Since this is not a Lync phone I installed Trixbox for the phones to register to.  The phones are working perfectly and can dial out.  I only need to be able to call the wireless extensions from Lync not the other way arround.  I have added in a gateway to the topology builder and built a route to go to the Trixbox server but I get an error message:


    The mediation server service has recieved a call that does not support comfort noise.  This event is throttled after 5 calls from a single gateway.  The mediation servcer service has recieved a call that does not support comfort noise from the gateway peer,

    Cause: The gateway peer does not support comfort noise.

    Resolution:  ensure the comfort noise option on the gateway has been enabled.


    I have searched and have been unable to find out how to "enable" the comfort noise.  Any one have any help???

    Tuesday, January 25, 2011 9:36 PM


  • Lync server 2010 requires gateways to support comfort noise codec which is announced in SDP as:

    a=rtpmap:13 CN/8000

    Before doing silence suppression this codec is used to inform the other side about current noise level so that synthetically created comfort noise can start using the same amplitude.

    One of many reasons why officially qualified gateways should be used together with Lync.

    Johann Deutinger | MCTS Exchange 2007/2010 / OCS 2007 | ucblog.deutinger.de
    • Proposed as answer by jwdberlin Thursday, January 27, 2011 8:52 PM
    • Marked as answer by jyoungjr Wednesday, April 13, 2011 2:23 AM
    Wednesday, January 26, 2011 10:06 PM