Consider the following scenarios:
- During a Microsoft Lync online conference, an audio conferencing provider (ACP) user joins the conference by using a land line or by using a mobile phone.
- A conference attendee starts the video call by using Lync 2010.
- An ACP user joins a Lync online conference.
- A conference attendee starts the video call in the conference.
- Another user joins the conference.
This issue occurs because Unified Communications Client Platform (UCCP) does not correctly parse the tel: URL that is used by the ACP participant.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.