Application service, Conferencing Attendant, and Conferencing Announcement have the same server hardware requirements as Front End Servers. For details about hardware requirements, see Server Hardware Platforms in the Supportability documentation.

Application service, Conferencing Attendant, and Conferencing Announcement have the same operating system requirements as Front End Servers. For details about software requirements, see Server and Tools Operating System Support in the Supportability documentation.

Conferencing Attendant and Conferencing Announcement require that Windows Media Format Runtime is installed on Front End Servers running Windows Server 2008 R2 or Windows Server 2008. The Windows Media Format Runtime is required to play Windows Media audio (WMA) files that are used for music on hold, recorded names, and prompts. The Windows Media Format Runtime is installed automatically when you run Setup, but you might need to restart the computer. Therefore, we recommend that you install Windows Media Format Runtime before you run Setup.

The following table describes the ports that are used by dial-in conferencing. If you use a load balancer, ensure that the load balancer is configured for the ports used by any applications that will run in the pool.

These ports are default settings that you can change by using the Set-CsApplicationServer cmdlet. For details about this cmdlet, see the Lync Server Management Shell documentation.

Note:
All instances of the same application in a pool use the same SIP listening port.

Ports used by dial-in conferencing

You can use the following client to schedule on-premises conferences that support dial-in access:

• Online Meeting Add-in for Microsoft Lync 2010 (installed automatically when you install Microsoft Lync 2010 or Lync 2010 Attendant)
  
  

The Dial-in Conferencing Settings webpage supports the combinations of operating systems and web browsers described in the following table.

Important:
The Dial-in Conferencing Settings webpage is not supported on 64-bit browsers.

Note:
32-bit and 64-bit versions of the operating systems are supported.

Supported Operating Systems and Web Browsers

Lync Server 2010 does not support customization of voice prompts and music for dial-in conferencing. However, if you have a strong business need that requires you to change the default audio files, see Microsoft Knowledge Base article 961177, "How to customize voice prompts or music files for dial-in audio conferencing in Microsoft Office Communications Server 2007 R2," available at http://go.microsoft.com/fwlink/?LinkId=179684.

Conferencing Attendant and Conferencing Announcement have the following requirements for music on hold, recorded name, and audio prompt files:

• Windows Media Audio (WMA) file format
  
  
• 16-bit mono
  
  
• 48 kbps 2-pass CBR (constant bit rate)
  
  
• Speech level at -24DB
  
  

Dial-in conferencing users must have a unique phone number or extension assigned to their account. This requirement supports authentication during dial-in. Enterprise users (that is, users who have Active Directory Domain Services (AD DS) credentials and Lync Server accounts within your organization) enter their phone number (or extension) and a personal identification number (PIN) to dial in to conferences as an authenticated user.