OCS R2 and existing SIP based PBX RRS feed

  • Question

  • Hi everybody

    I would like to install OCSR2 standard as an departemental installation and slowly move users from an existing SIP based IP PBX to OCSR2.
    My installation should not be bigger than 25 users when I am finished.

    Now the question:
    If I install an OCSR2 after the existing SIP based PBX, which is connected to the outside PSTN, do I then need to install a Mediation Server on a separate server between the OCSR2 and the PBX?

    Every user need to have an PBX based deskphone and Communicator running at the same time, and the user should be able to control the deskphone from Communicator

    /Birger Madsen
    Thursday, March 12, 2009 7:33 AM

All replies

  • Hi,
    If you want OCS clients to be used as softphones - making calls from OCS to your PBX phones & vice versa - then yes you need a mediation server. The SIP trunk that you set up on your IP PBX should be configured to communicate with the Mediation server.

    By the way - if you want your MOC client to control the PBX phone you either need to have a PBX that support Remote Call Control (very few) or use a presence gateway like GETS. MY advice: don't bother trying to do Remote Call Control. Either use the PBX for voice, or OCS for voice. Or heck, even use both at the same time for voice. But don't bother with RCC.


    Matt McGillen, PointBridge - https://blogs.pointbridge.com/Blogs/mcgillen_matt/default.aspx
    Thursday, March 12, 2009 2:25 PM
  • Hi Matt 

    Thank for your quick answer. :-)

    So, using RCC is not the best way to go, OK.

    How about using CSTA, will that make the same problem as with RCC?


    Birger Madsen

    Thursday, March 12, 2009 2:38 PM
  • Hi Birger,
    RCC actually uses CSTA as the protocol to handle all the RCC events. So I don't think there is a way to use CSTA in OCS, except for RCC.

    Now I should say: if your PBX does support RCC, by all means try it. But if you need to upgrade/buy/go to trouble to make it support RCC, then I'd say it's not worth it, especially since it looks like you are going to be completely off the old PBX when this is all done.

    My advice would be to see if you can configure the PBX to also ring users' communicator extensions at the same time as ringing the PBX phone. Kind of a "dual ring" so that users can pick up calls on either during the transition phase.

    You'll need to do something clever with your IP PBX's dial plan, like create a "routing code" to get calls from the PBX over to OCS. Like 55XXXX will route calls to OCS. Then OCS strips the 55 routing code off and normalizes the number. (that way you use the same ext. in the PBX as OCS).

    Hope that helps!



    Matt McGillen, PointBridge - https://blogs.pointbridge.com/Blogs/mcgillen_matt/default.aspx
    Thursday, March 12, 2009 2:43 PM
  • Hi

    The a Siemens PBX there is a feature called MULAP.

    A MULAP is a "main" extension with several extension underneath. The main extension number could be 100 and the underlying extension could be 101 and 102.
    Then, when you dial 100, both 101 and 102 will ring. If 101 picks up the phone, no one can ring to 100. They get a busy tone until 101 hangs up! On the other hand, when 101 or 102 rings out, the called number will see 100 in the display.

    I dont know if this is called Forking, but it is very close to.

    Extention 101 and 102 could be a PBX deskphone, a DECT phone or a SIP based phone.

    Do you think it is possible to register an OCS based extension to the PBX as an extension through the mediaion server?


    Birger Madsen

    Thursday, March 12, 2009 3:30 PM