How to Turn On PSTN Conferencing in Microsoft Teams

PSTN (Public Switched Telephone Network) conferencing in Microsoft Teams allows meeting participants to dial in from any telephone, making meetings accessible to users without internet connectivity or a Teams client. Turning on PSTN conferencing requires specific licensing, bridge configuration, and policy settings that must be configured correctly for enterprise-grade reliability. EPC Group has enabled PSTN conferencing for organizations with thousands of users across dozens of countries, and this guide reflects the process we follow for every deployment.

What Is PSTN Conferencing?

PSTN conferencing -- also referred to as Audio Conferencing in Microsoft's current terminology -- connects the traditional telephone network to Microsoft Teams meetings. When enabled, meeting invitations include a dial-in phone number and a conference ID. Callers dial the number, enter the ID, and join the meeting audio alongside participants using the Teams app, web browser, or Teams-certified devices.

Key capabilities of PSTN conferencing include:

• Dial-in - Participants call a toll or toll-free number to join meeting audio
• Dial-out - The meeting system calls a participant's phone number to add them
• DTMF controls - Phone participants can mute/unmute (*6), raise hand (*5), and hear a roster (*1) using their keypad
• Conference bridge - Microsoft-hosted infrastructure that routes calls to the correct meeting
• Global coverage - Dial-in numbers available in 90+ countries and regions

Step 1: Verify Your Microsoft 365 Licensing

PSTN conferencing requires the Audio Conferencing license for each meeting organizer. The license is included in certain plans and available as an add-on for others:

• Included in: Microsoft 365 E5, Office 365 E5, Microsoft 365 A5 (education)
• Add-on required for: Microsoft 365 E3, E1, Business Standard, Business Basic, F1, F3
• Pay-per-minute option: Available for organizations with low dial-in volume

If you plan to offer toll-free dial-in numbers, you also need Communication Credits, a prepaid balance that covers per-minute charges for toll-free inbound calls and dial-out calls to certain countries.

Step 2: Assign Licenses in the Admin Center

1. Sign in to admin.microsoft.com with a Global Administrator or License Administrator account
2. Navigate to Users > Active users
3. Select the users who organize meetings requiring PSTN dial-in
4. Click Licenses and apps and check Audio Conferencing
5. Confirm each user has a Usage location set (required for phone number assignment)
6. Click Save changes

For bulk license assignment, use PowerShell with the Microsoft Graph module:

Step 3: Configure the Conference Bridge

1. Go to admin.teams.microsoft.com > Meetings > Conference bridges
2. Review the automatically assigned phone numbers for your tenant
3. Click Bridge settings to configure:
   • Entry/exit notification type (tones, name announcement, or none)
   • PIN length for organizer authentication
   • Automatic email notifications when settings change
4. To add additional numbers: click Add and submit a request for service numbers in your target countries
5. Set the default bridge number that appears first in meeting invitations

Step 4: Enable Communication Credits (Optional but Recommended)

Communication Credits are required for toll-free dial-in and for dial-out to certain countries. Even if you do not need toll-free immediately, setting up Communication Credits prevents service disruption if your organization decides to enable these features later.

1. Go to admin.microsoft.com > Billing > Purchase services
2. Search for Communication Credits and complete the purchase
3. Set an initial funding amount (we recommend starting with $100-$500 for pilot)
4. Enable Auto-recharge with a trigger amount and recharge amount to prevent service interruption
5. Assign the Communication Credits license to users who need toll-free or dial-out access

Step 5: Validate and Go Live

1. Have a licensed user create a test meeting and confirm the dial-in number appears in the invitation
2. Dial the number from an external phone and enter the conference ID
3. Verify audio quality is clear in both directions
4. Test DTMF controls: mute (*6), raise hand (*5)
5. If toll-free is configured, test the toll-free number and verify Communication Credits are deducted
6. Check the PSTN Usage report in Teams admin center to confirm the test call was logged
7. Roll out to the broader organization with a communication plan that includes the dial-in number and instructions

Why Choose EPC Group for PSTN Conferencing

With 29 years of Microsoft enterprise consulting, EPC Group brings deep expertise in Teams telephony including PSTN conferencing, Phone System, Direct Routing, and Operator Connect. We handle the full lifecycle from planning and licensing through number porting, bridge configuration, policy design, and ongoing operations.

• Enterprise-scale deployments across 90+ countries
• Legacy PBX and conferencing provider migration
• Number porting with zero-downtime transition planning
• Compliance-aligned configurations for HIPAA, SOC 2, FedRAMP
• 24/7 managed services for Teams telephony infrastructure

Frequently Asked Questions