Mark Brezicky / / Categories: Best Practices

Enable users for Skype for Business Cloud PBX with on-premises PSTN Calling

Microsoft’s Skype for Business Cloud PBX has been relevant in the market for some time now.  However, there is still some hesitancy to commit to a full cloud solution due to initial limitations with Microsoft’s Cloud PBX solution. While Cloud PBX continues to develop into a true Enterprise PBX solution, there are several components that are still not supported, such as common area and analog phones, that will prevent many sectors from moving entirely to the cloud.  Microsoft has created several scenarios to allow for customers to maintain their on-premises PBX and/or SIP Trunks while still having users in Skype for Business Online.  These include Cloud Connector Edition and Cloud PBX with on-premises PSTN calling utilizing an existing Skype for Business deployment.  This has allowed for customers to start utilizing Cloud PBX for their users at their own pace even if they are not able to able to fully move to the cloud.  The following will discuss the high-level requirements needed to start using Cloud PBX if you already have an on-premises Skype for Business Enterprise Voice deployment.


Requirements for Cloud PBX users to have on-premises PSTN Calling:

  • On-premises Skype for Business or Lync Server 2013 deployment
    • Lync Server 2013 must be using Skype for Business Edge servers
  • Active Directory synchronization
  • On-premises Enterprise Voice fully configured
  • Skype for Business hybrid deployment
  • Devices should have the latest firmware installed
  • Create a Voice Routing Policy or modify the Global policy
    • Set-CsVoiceRoutingPolicy -Identity Global -PstnUsages "Internal","Local","Long Distance"


Enable user for Cloud PBX w/on-premises PSTN Calling

The steps below list the high-level process of migrating an on-premises Skype for Business Enterprise Voice user to Skype for Business Online Cloud PBX:

  1. Enable the user for Enterprise Voice on-premises
  2. Assign a Voice Routing Policy
    1. Grant-CsVoiceRoutingPolicy -Identity Username -PolicyName Policy
    2. If using global no need to assign a policy individually
  3. Assign Cloud PBX and PSTN Conferencing license to the user
    1. If phone number is not ported to Microsoft do not assign PSTN Calling license
  4. Move user(s) to Skype for Business Online
    1. Use SFB Control Panel OR
    2. Run the following commands:
      1. $creds=Get-Credential (Global Admin Credentials)
      2. Move-CsUser -Identity -Target -Credential $creds -HostedMigrationOverrideUrl *
    3. Enable user for Cloud PBX and Voicemail
      1. Connect to Skype for Business Online PowerShell

Import-Module skypeonlineconnector

$cred = Get-Credential

$Session = New-CsOnlineSession -Credential $cred -Verbose -OverrideAdminDomain

Import-PSSession $session

  1. Enable user for Enterprise voice and Voicemail

Set-CsUser -Identity -EnterpriseVoiceEnabled $true -HostedVoiceMail $true

*URL may be different.  To determine which URL to use open Skype for Business Online Admin Center to determine which admin site is being used (i.e. admin0a)


Key items to consider for Cloud PBX users with on-premises PSTN Connectivity

  • Do not assign PSTN Calling license if using on-premises PSTN connectivity.
    • You cannot mix inbound and outbound calls between Microsoft PSTN calling and on-premises PBX. All inbound and outbound calls either need to use on-premises PSTN connectivity or Microsoft PSTN Calling connectivity.
  • Each user requires PSTN Conferencing license for dial-in conferencing capabilities. This is typically included with Office 365 E5 licenses.
  • Any scheduled meeting will automatically update with a Skype for Business Online URL within an hour or so. New meeting invites will be sent to meeting participants.
  • Client Policies may be different than what is configured on-premises.
  • There is still no Persistent Chat in Skype for Business Online.
  • Voicemail is provided by Azure Voicemail, not Exchange Unified Messaging.
  • Voicemail access does not have a PSTN number for Subscriber Access.
    • The voicemail dial plan is 8 digits.  Your extension is the last 8 digits of your phone number; however, you can still connect to the Subscriber Access from your Skype for Business client.


There are many other factors to consider when moving to a cloud-based solution such as security and networking.  Enabling Technologies can help you properly prepare for moving to Skype for Business Online based on Microsoft Best Practices.  You can check out our more in our Move it to the Cloud section on our website.

Work with our team of Cloud Computing Consultants who have done this so many times they know all of the “minefields” to prevent missteps.