Office 365 Skype for Business Online: PSTN Audio Conferencing Myths Exposed and Frequently asked Questions!

Editor’s note: The following post was written by Office Servers and Services MVP Dino Caputo as part of our Technical Tuesday series.  

Microsoft offers a mature and feature rich PSTN Audio Conferencing service in both Skype for Business Server and its cloud version dubbed Skype for Business Online PSTN Audio Conferencing. As announced back in November 2015 Microsoft has brought the entire Unified Communications stack including Enterprise Voice and PSTN Audio conferencing into Office 365 as part of Skype for Business Online.

The new services include the following:

PSTN Conferencing: provides the flexibility to dial in to a meeting from a traditional phone, in addition to the existing ability to join a meeting with a single click on your PC or mobile device.

Skype Meeting Broadcast: makes it easier than ever to produce large virtual meetings for up to 10,000 meeting attendees, who can join from virtually any browser or device (see it in action). Now Skype for Business truly is a single platform for every type of meeting.

Cloud PBX: enables companies to eliminate separate PBX systems and transition to the cloud with Office 365 as the central location to manage users for communication

PSTN Calling, Office 365 customers can also subscribe to Microsoft managed calling plans and phone numbers in 196 countries with more countries being added.

For, many of these organizations one of the primary reasons of moving to Skype for Business was the cost savings realized with the PSTN Audio Conferencing feature. Here are the top myths and frequently asked questions I often get about this service.


Is Office 365 Skype for Business Online PSTN Conferencing really like my old and trusty conference bridge?


Absolutely and more! Skype for Business Online PSTN Conferencing offers everything that your traditional conferencing bridge did with many more features. First and foremost, you can absolutely provide like for like functionality in the most common and basic scenario where a user dials the number to their PSTN conference bridge, enters their Conference ID, PIN and is in their bridge ready to participate in a meeting.   PSTN Conferencing in Skype for Business Online enables attendees to join online meetings from any telephone line by dialing a local access number, and dial out from a meeting to add others when needed. Of course you can also do single-touch join options from your PC, smartphone, and browser.  While Microsoft offers 64 local dial in conferencing numbers today with more added regularly, Toll Free numbers are not yet available. My understanding is that these will be added.


Do users always need a PIN to join a Skype for Business Online Meeting?

This is a very common one and the answer 99% of the time is “No, you won’t need a PIN to join your meeting if you join via a Skype for Business client (desktop or Mobile) You see, since you are already authenticated using a Skype for Business client you won’t need to enter a PIN to start your meeting. You simply click the Join link to start the meeting!

You will however need a PIN if you are going to join a Skype online meeting both as the organizer and via your phone that is not running the Skype for Business Mobile client. For example, say you are at the cottage for the weekend with no internet but you do have a phone line. In this case you can do the following:


  1. Get a PIN in advance of your meeting! When you were enabled for PSTN Conferencing you should have received an email with your PIN. If you can’t find this email or need a new PIN please ask your administrator to send you a new PIN.
  2. You can now use your PIN to join the meeting as the organizer via your phone.

Note: Microsoft is currently investigating the option to allow Office 365 users to ability to self request and reset PINs.


How does a Skype for Business Online user schedule a Skype for Business Online meeting with dial-in meeting details?

When a user is assigned a Skype for Business PSTN Conferencing license and the user creates a new Skype for Business meeting in Outlook or the Outlook Web App, the dial-in phone numbers and conferencing IDs are added to the meeting invite.


The following are the default behavior options for the meeting.


  1. Everyone will have access to the meeting including people outside the company
  2. People dialing in by phone will wait in the lobby until the meeting organizer joins the call
  3. Meeting presenters (if using the Skype for Business client) will be able to present content if they are people from within the company that scheduled the meeting.

These options can be modified when using the Outlook client or the Skype for Business Web Scheduler.



How do I Join my Skype Meeting conference call using a regular Phone?

This frequently comes up especially for new users to Skype that still feel the need to use a traditional phone or mobile phone (no Skype for Business mobile client installed) or just want to have the peace of mind that this will truly work from any phone.

  1. Please ensure you have previously set your PIN as outlined in the previous section.
  2. Open the meeting request, and, under the Join by phone, note the dial-in numbers and conference ID. You can also click the Find a local number link in the invitation to see if additional dial-in numbers are available.
  3. Dial one of the numbers listed, and, when prompted to do so, enter the conference ID, followed by the pound sign (#).
  4. When you hear “If you scheduled the meeting, press the star (*) key when you hear the prompt, and then enter your PIN.” Press the * Key.

You will hear “You are now joining the meeting as a leader” and will be connected to the call.

Note   If you are placed on hold or asked to record your name, then you were not authenticated as the conference call leader. Hang up and try joining the conference call again.


What DTMF commands are available to me while in the meeting?

During the meeting you may manage participants, audio, and the lobby by using the DTMF cmmands shown in the following table.



About the author

Dino is a senior consultant within the Softchoice Microsoft UC Practice with overall accountability for architecture and design of unified communications solutions for Softchoice customers. He holds many certifications including an MCSE, and is a Microsoft Certified Technology Specialist in Live Communications Server (LCS) 2005, Office Communications Server (OCS) 2007 and a MCTS in Lync Server 2010 and 2013.   Dino led the initiative to certify Bell Canada within the Microsoft Voice-Ready Partner Program (VPP) demonstrating Bell’s deep technical understanding of Unified Communications. Dino was also part of the first team to successfully deploy and integrate Microsoft Office Communications Server 2007 with Nortel’s Converged Office Solution on the Communications Server 1000 IP/PBX (CS1K).

Comments (3)

  1. Guy Gordon says:

    I believe MSFT is offering unlimited conferencing for a fixed monthly price, do you know how they will be pricing the Toll Free access numbers when they will be adding that capability?

  2. Tiago F. says:

    What CAL do i need to deploy for dial-in and dial-out via PSTN to my Users ?

  3. JLyall says:

    How can I either set the PIN to a specific number or make it not required?

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