Chris Stegh / / Categories: Partner & Customer Updates, Microsoft Skype for Business

End of support for Exchange Online Unified Messaging (UM) voicemail in conjunction with third-party PBXs Update

This is a follow up to a prior blog about end of support of third-party PBXs connecting to Exchange Online Unified Messaging through third party SBCs.

Several third-party vendors have provided more information about how they can handle the issue.  Since most of Enabling’s customers have existing Audiocodes’ SBCs, some additional detail is provided here on their solution.  Links to other options from anynode and Sonus are below.

These third-party vendors support Microsoft’s option 3, where customers retain their PBX and continue to use Exchange Online Unified Messaging (ExOL UM).  But instead of using existing SBCs to connect, they connect to ExOL UM via a combination of a new SBC and Skype for Business Server on premises.  If SfB on premises is not installed yet, these SBCs can support the necessary components within their hardware appliance.

An existing SBC combined with SfB on premises would support some but not all ExOL UM capabilities.  Existing SBCs and SfB would simply push voicemail calls from the PBX to Exchange, but features like MWI, Play on Phone, redirected calls from Auto Attendants, require the new SBC.  The new SBC’s API to Skype is in place to “extract” that information and forward to the legacy PBX.  Otherwise those MWI and redirected calls will stop at SfB and never hit the legacy PBX. 

More notes from the AudioCodes webinar on their X-UM solution: 

  • Availability is expected before, during or right after Ignite (week of 9/25) 
  • X-UM Lite will be available as an appliance or software solution 
  • X-UM Lite will work with older Lync/Skype versions as long as Edge requirements are met 
  • Licenses:
  • Must have MSFT SfB Front-End server (either standing along or inside the X-UM box)
  • Must have Skype voice licenses (E5 or Plus CAL) for Exchange UM users
  • X-UM Lite cannot collocate on Skype server, since it is a UCMA app and not supported by Microsoft. 
  • X-UM Lite cannot be deployed on OSN modules in existing SBCs, however, discounts exist for current customers will be provided to protect investment 
  • To patch the servers, use Standard Edition SfB bits, and follow standards of your org (SCCM/WSUS, etc.)
  • PBX-based phones can listen to voicemail by dialing a Subscriber access #, PIN, etc.  

AudioCodes X-UM solution is an option for a) existing AudioCodes SBC customers b) small to large scale   organizations c) no SfB on premises (optional).  For more about Audiocodes X-UM, see


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