Article ID: 2254369 - View products that this article applies to.
Participants in a conference call that is hosted by Audio Video Multipoint Conferencing Unit (AVMCU) using Microsoft Lync Server 2010 or Microsoft Office Communications Server 2007 R2 cannot add attendees to the conference if those attendees require Dual Tone Multi Frequency (DTMF) tones to join the conference. This issue may occur in the following scenarios:
The AVMCU feature in Lync 2010 or Office Communications Server does not support DTMF relay.
To work around this issue, use the Lync 2010 client or the Office Communicator client to make a peer-to-peer call to the remote party that requires DTMF tones. After you are connected to this remote party as a peer, add the other participants to the conference. This workaround will resolve the issue in scenarios where only one participant requires the client to transmit DTMF to connect it to the conference.
Article ID: 2254369 - Last Review: October 28, 2010 - Revision: 8.0