Working with PSTN Conferencing in your Office 365 Skype for Business Online Tenant.
ID PSTN -> SfBOnlUsr call
Start and instant (Impromptu) Meeting or schedule a Online Meeting as usual from Outlook or your Client App. After the meeting is escalate into ConfCall, the MCU SfB OnLine Server will send reinvite to MediationServerHybrid.
This is illustrated in the drawings below.
First we have a look into the outbound call to a PSTN user:
Configure online hybrid Mediation Server Settings
The setup process is curial and needs to be follow as below:
When a P2P call is escalated to a PSTN conference, the Skype for Business Online conferencing server will send an invite to the Cloud Connector Mediation Server. To ensure that Office 365 can route this invite successfully, you need to configure a setting in your online tenant for each Cloud Connector Mediation Server as follows:
Use the default SIP domain of Cloud Connector (the first SIP domain in the .ini file) as the user domain.
Do not assign any Office 365 licenses (such as E5) to the account you create. Wait for Office 365 AD sync to complete.
2. Start a tenant remote PowerShell session using your tenant admin credentials, and then run the following cmdlet to set the Mediation Server and Edge Server FQDN to that user account, replacing <DisplayName> with the Display Name of the user for the account you created:
Set-CsHybridMediationServer -Identity <DisplayName>
-Fqdn <MediationServerFQDN> -AccessProxyExternalFqdn <EdgeServerExternalFQDN>
-Fqdn <MediationServerFQDN> -AccessProxyExternalFqdn <EdgeServerExternalFQDN>
3. For Identity, use the Display Name of the Office 365 user account you created for this Mediation Server.
For MediationServerFQDN, use the internal FQDN defined for your Mediation Server.
For EdgeServerExternalFQDN, use the external FQDN defined for Edge Server Access Proxy. If there are multiple Cloud Connector PSTN sites, choose the Edge Server Access Proxy FQDN assigned to the site where the Mediation Server is located.
4. If there are multiple Cloud Connector Mediation Servers (multiple-site, HA), please repeat the previous steps for each of them.
https://technet.microsoft.com/EN-US/library/mt740651.aspx
Further conference expansion with Dial-In and Dial-Out from/to PSTN:
If another User should be called into the conference the Microsoft Office 365 PSTN Conferencing Bridge breakout is used.NOTE:
Dial-Out will be charged within your Office 365 Subscription.
If you have PSTN Calling activated, the outbound call with be deducted from your PSTN Calling minutes, or individually charged based on the Microsoft Destination minute pricings.
Other Users calling into the conference with PSTN, use the Dial-In Bridge in Office 365 Skype for Business.
Author: Thomas Poett MVP, Business Unit Lead Microsoft Unified Communication