Lync Server 2010 Join Meeting Audio Scenarios

With Lync Server 2010, conferences provide the option to dial out to participants. The dial out to PSTN experience varies depending on whether the organizer and participant are enabled for Enterprise Voice. This article covers the possible scenarios in this user experience.

Author: Rui Maximo with Geoff Clark

Publication date: June 2011

Product version: Lync Server 2010

When participants join a Lync conference using the Join Meeting Audio, Call me at option, as shown in Figure 1, the A/V Conferencing Server dials the user’s PSTN phone number. This experience varies depending on whether the participant and the organizer are enabled for Enterprise Voice.

Figure 1. Call me at option


There are four possible scenarios:

1. Both the organizer and identified participant are enabled for Enterprise Voice.

2. Only the organizer is enabled for Enterprise Voice and the participant is either

a. Anonymous

b. Not enabled for Enterprise Voice

3. Only the participant is enabled for Enterprise Voice.

4. Neither the organizer nor the participant are enabled for Enterprise Voice.

Let’s examine these scenarios in more detail.

In scenarios 1 and 3, Lync Server uses the participant’s voice policy and dial plan normalization rules to dial the PSTN phone number. The call is routed to the Mediation Server, through the gateway to the PSTN. The user cannot be anonymous.

In scenarios 2.b and 4, Lync Server cannot dial the PSTN phone number, because the participant is not enabled for Enterprise Voice. Lync Server cannot find a voice policy associated with the user to enforce call routing. This behavior is expected and by design.

In scenario 2.a, where the user is anonymous, Lync Server dials the anonymous user using the organizer’s dial plan and voice policy.

Here’s an example:

Jim creates a Lync meeting and invites Michele, Patrick, and Ryan as participants.

Jim is not enabled for Enterprise Voice. Therefore, when Jim joins the meeting, his audio connects through his computer and is not routed as a voice call.

Michele is an anonymous user. When she attempts to join the meeting using the Call me at feature, the call fails, and she is unable to connect to the meeting’s audio. Michele must dial directly into the meeting.

Patrick is enabled for Enterprise Voice. When he tries to join the meeting using the Call me at feature, the call comes in, and he joins the audio portion of the meeting.

Ryan is not enabled for Enterprise Voice. When he uses the Call me at feature to connect to the meeting audio, his PSTN phone never rings. The PSTN call cannot be routed, because there’s no voice policy to enforce.

The only option for A/V Conferencing Server to dial PSTN phone numbers (using the Call me at feature) for non-enabled Enterprise Voice users (PC-to-phone) is to configure a static route on the Mediation Server to allow all outbound calls. However, this configuration is not recommended, because it allows any Lync client to make outbound calls to any phone number. The Mediation Server translation rules are not applied, because this call is routed through a static route and not through Enterprise Voice outbound routing rules.


The Lync Server Call me at option dials out to the participant to join the audio portion of a Lync meeting. This feature requires the participant to be enabled for Enterprise Voice. If the participant is a Lync user, but not enabled for Enterprise Voice, Lync Server cannot call the participant’s PSTN phone number. If the participant is an anonymous user, Lync Server uses the organizer’s dial plan and voice policy to call the anonymous user.

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Comments (8)
  1. Jamie Stark says:

    Sorry for the delay in reply…

    First, completely agree on your read of the licensing guide that this is an ECAL feature.   Essentially this is an area where the unified design of the product doesn’t intersect perfectly with the somewhat arbitrary licensing model that is overlaid on top.

    This can work in Lync, but the default out-of-the-box configuration doesn’t have it enabled.  It’s essentially the same case we had in OCS 2007 R2 with dial-out from Communicator Web Access – that’s documented here:…/dd425101(office.13).aspx
    .  Then Tom took this a step further on his personal blog and documented it out for configuring in Lync:…/lync-dial-in-conferencing-static-route-configuration

    Certainly we’ve taken the feedback that this has some room for improvement – we’re currently looking at the best way to do so without compromising the core unified design or having an onerous overhead on admins.  Can’t comment on timing though at this stage.

    Hope this helps


    Lync Product Manager, Microsoft



  2. Jason says:

    Jamie Stark – Any updates on this?  Any official documentation?  We want to leverage the Enterprise feature as described in the license but are apprehensive to use what does not appear to be a fully supported solution (nor completed documented solution) to the problem.

    The License is clear (for a change), the feature and documentation on how to use the feature is nonexistent!

    For anyone who has done this, does this simply leverage the existing PSTN gateway that is configured for inbound conferencing?  Does the addition of this route hurt us later if we want to add the Plus cal for some of our users?

  3. adam says:

    What if you have a user, not RCC or EV enabled, that wants to use a conference room with either a Lync Common Area phone or a legacy pbx phone? Would that user be out of luck because they aren't EV enabled?

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