Simultaneous Ringing Disabled for Response Group Service Calls in Office Communications Server 2007 R2

Communications Server 2007 R2

Calling an additional phone number during a Response Group call might mean ending up in a voice mail system. Learn how to avoid making such a call. This article, originally posted on the Communications Server blog, is worth a second glance.

Author: Stéphane Cavin

Publication date: April 2010 (originally published July 2009)

Product version: Microsoft Office Communications Server 2007 R2

Why is it important to not call the user’s additional phone number for Response Group call? In this article, we’ll explain this and show you how to avoid making this call.

The main goal of the Response Group Service is to route calls to individuals. When simultaneous ringing has been enabled, a user has set their forwarding settings to call an additional phone number. Doing so means that there is a chance that the call can end up on a voice mail system; for example, the voice mail of the user’s cell phone. It wouldn’t make sense to have calls routed from a Response Group to someone’s voice mail. This is the reason why simultaneous ringing is not applied to Response Group calls.

Disabling simultaneous ringing is achieved by setting a special header in SIP INVITE that is sent by the service to Microsoft Office Communications Server 2007 R2. It then interprets this header and doesn’t apply the user’s forwarding settings.

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Not all the user’s call-forwarding settings are applied.

The forwarding settings are as follows:

  • Ring me and my team-call group
  • Forward to my voice mail, a number, or a contact
  • Ring me and my delegates
  • Ring my delegates only

If one of these settings is selected, Office Communicator Server won’t honor the setting for Response Group calls.

If “Ring my delegates only” is selected, neither the user nor their delegates ever receives any Response Group calls. The “Ring for this many seconds before redirecting” option is ignored. The call rings for as long as it has been configured to do so in the Response Group agent group settings on the Polices tabbed page of the New Group Properties dialog box. The agent alert time is shown in seconds.

Disabling simultaneous ringing is not applied to Response Group call. This helps you avoid being sent to a user’s voice mail.


Comments (2)
  1. Jonatan says:


    "Disabling simultaneous ringing is achieved by setting a special header in the SIP INVITE sent by the service to OCS. OCS will then interpret this header and not apply the forwarding settings of the user."

    Exactly what is this special header? And is it the same with Lync?

    Thanks in advance

  2. stephane says:

    Hi Jonatan,

    Yes, the behavior is the same on Lync. The headers are documented in MS-SIPRE:…/cc431509(v=office.12).aspx

    A header of interest is the ms-sensitivity header, section 2.2.9.



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