The purpose of this article is to explain what type of Office 365 licenses can or should be used with any of the various phones and meeting devices qualified by Microsoft for Skype for Business Online.  These products can natively register to Skype for Business Online using resource accounts which must be assigned the correct licensing.  This covers equipment like the many different IP Phones from five different partners or the several different Meeting Room platforms like the older Lync Room Systems, newer Skype Room Systems, or even the recently qualified Polycom Group Series to name a few.

The guidance covered in this article is not necessarily applicable to desk phones which are assigned to a specific user, as those users would already have an assigned Office 365 license which applies to any client and devices they sign into with their own credentials.  It is the meeting room solutions and other similar shared resources like conference room phones or common area phones which utilize their own dedicated account which are the focus of this article.


As with any device that is registering to Skype for Business Online, be it a phone or video system, a licensed Office 365 account is required.  This can be a standard Skype for Business user or a special Meeting Room account.  Generally it is a best practice to use the Meeting Room account which affords the registered device some unique capabilities and behaviors, but it is not a requirement.  This previous article focusing on Online Meeting Room Accounts covers in detail the different configuration options and guidance around each type.

Once an account is created for the device then a valid Office 356 license needs to be allocated to it before it can be used to register a device.  Typically an empty meeting room might already have an Exchange Online Room Mailbox configured for it which incurs no cost and consumes no license in Office 365, but that is only for room reservation capabilities.  Once that meeting room is equipped with a dedicated Skype for Business device then a Skype for Business license must be assigned to that account, which is not free.

This means that the devices need only to be concerned with the Skype for Business Online portion of licensing.  The Exchange Online portion of the device’s account is still only a Room Mailbox, so then there is no need for Exchange Online plans to be assigned.  That being said many of the Office 365 licensing plans already include Exchange Online licensing so unless dealing with a standalone plans this point is moot.

Office 365 Plans

For those unfamiliar with the various Office 365 licensing plans the following is a list of the current plans which provide Skype for Business Online services in them.  The items in red are the default recommended options in each class and the reasoning for each is explained below.

Standalone Plans

  • Skype for Business Online Plan 1
  • Skype for Business Online Plan 2

Business Plans

  • Business Essentials
  • Business Premium

Enterprise Plans

  • Enterprise E1
  • Enterprise E3
  • Enterprise E5

The absolute minimum Office 365 license required for a device would be a standalone Skype for Business Online Plan 1 license.  But that plan is not recommended based on its limitation of only being able to join other meetings and not create ad-hoc or scheduled meetings.  On the surface this may not seem like a problem as users would not be sending meeting invitations from device’s account, they create or schedule meetings using their own Skype for Business account.  But what about when a user walks into a conference room that is not booked and simply wants to start an ad-hoc meeting?  Or what about adding new participants into an active meeting from the device itself?  Scenarios like those are covered under the Meeting Scheduler capabilities which are included in the standalone Skype for Business Online Plan 2 tier, hence this being the recommended minimum Office 365 license.

But most Office 365 subscribers today are typically not using the a la carte style standalone plans and are instead leveraging a Business or Enterprise plan.  All of the Business and Enterprise plans listed above automatically include Skype for Business Online Plan 2 in them, as illustrated by the following example showing an Enterprise E3 license expanded to list some of the includes services.


Note the Skype for Business Online (Plan 2) option listed above.  Because all Business and Enterprise plans with Skype for Business leverage Plan 2 capabilities then any of these are sufficient to support joining scheduled meeting and creating ad-hoc meetings as explained earlier. This also illustrates why it is usually incorrect to assign a redundant standalone Skype for Business Online Plan license to an account which is already assigned one of the supported Business or Enterprise plans.

Now, when only a handful of shared devices are deployed in an environment it can be less administrative work to simply assign licenses to these accounts which are already available in the tenant.  Yet from a a cost-savings standpoint it can be overkill to assign a license which may include many additional features that the device is not capable of leveraging and never would be.

For example some of the plans listed above include licenses for Office applications which device do not need.  The reason that Business Essentials is recommended over Business Premium is that the more costly Premium license allows the account to install the Office suite software on multiple workstations, but a device-only account would never be used for that.  This same reasoning is why Enterprise E1 is generically recommended over the more costly E3 and E5 licenses as, like Business Essentials, it does not include the Office suite of applications.

That being said there are other arguments for using Enterprise licensing due to bundled add-on licenses.  In fact there are scenarios where even Business licenses are not valid and would need to be transitioned to Enterprise licenses.  These reasons will be explored in the next section.

Skype for Business Add-On Licenses

Some of the following value-add licensing options can provide additional capabilities to the solution depending on what the device is and needs to do.

Currently the available add-on licenses for Skype for Business Online are:

  • PSTN Conferencing: The Dial-In Conferencing services for joining meetings from a PSTN phone.
  • Cloud PBX: Traditional PBX functionality and support for integration with a traditional PBX system.
  • PSTN Calling: PSTN connectivity hosted directly by Microsoft Office 365.

Here is one area where Microsoft does have some official guidance available online when dealing with licensing Skype for Business devices.  This Office support article includes both details on the various Skype for Business add-on licenses as well as how they are applicable to the newer Skype Room System v2 platform.  Taking that one step further the various Skype Room System scenarios covered in the article can be extrapolated to any device.  Again this is not specific to a single conferencing product, any meeting device follows the same requirement and guidance.

That article includes a table which granularly lists various in-room scenarios and which licenses are required to perform those specific tasks.  As already mentioned there are differences between joining meetings and creating meetings from within the conference room itself.  The information on that support article may be a bit confusing to understand at first glance so the important information has been reworded for simplicity’s sake in the table below.

Standalone Business Enterprise
Join a
Skype for Business Online Plan 1 Business Essentials
Business Premium
Enterprise E1/E3/E5
Initiate an
Skype for Business Online Plan 2 Business Essentials
Business Premium
Enterprise E1/E3/E5
Invite PSTN
via dial-out
Skype for Business Online Plan 2
+ PSTN Conferencing
N/A Enterprise E1/E3 + PSTN Conferencing
Enterprise E5
Assign an
Enterprise Voice
phone number
to the device
Skype for Business Online Plan 2
+ Cloud PBX
+ PSTN Calling
N/A Enterprise E1/E3 +Cloud PBX + PSTN Calling
Enterprise E5 + PSTN Calling

The table above outlines how, for example, a video conferencing system may only need to be licensed for the basic ability to join meetings, but if it or a conference phone needs to also support the typical use-cases of placing PSTN calls or adding PSTN participants into a live Skype for Business meeting then additional licensing may be required.

  • The first two scenarios are already covered in the Meeting Scheduling capabilities included in any plan equivalent to Skype for Business Online Plan 2.  This underscores why using Plan 1 is not ideal as the second scenario is a common task performed in Skype for Business meetings.
  • The third scenario introduces the need for a PSTN participants to be invited on-demand to the meeting.  As mentioned earlier these meetings are typically scheduled by regular users who may already be granted a PSTN Conferencing licensing and the PSTN dial-in conferencing information would have been included in the original meeting invitation.  Thus, a PSTN caller can use that information to manually dial into a conference as usual.  But this third scenario in the table above is something different: it is the ability for someone in the conference room that is already connected to a meeting to use the device itself to manually add a new participant to the meeting, but using a PSTN phone number to call out to that desired attendee.  This action is performed on the device but the phone call actually comes directly from the Skype for Business Online service (not the meeting room device).  The callee is then brought directly into the meeting when answering the call on their PSTN phone.  Assigning a PSTN Conferencing add-on license to a supported plan, or using an Enterprise E5 license will provide this capability.
  • The fourth scenario is not related to Skype for Business meetings at all.  This is simply the ability to assigned a PSTN phone number directly to the device so that it can place and receive peer-to-peer calls to and from the PSTN.  Including Cloud PBX is the step, followed by either getting a PSTN Calling plan directly from Microsoft or connecting to a traditional PBX with PSTN connectivity.

Important details to further understand the guidance in this table are that (1) the Enterprise E5 plan already includes the PSTN Conferencing and Cloud PBX licenses and (2) that while all three add-on licenses can be used with Standalone and Enterprise plans they cannot be used with any of the Business plans.

So, if an account with a Business plan needs to leverage some Skype for Business PSTN features there are two potential paths. The recommended option is to simply transition to an Enterprise license for that account.  An alternative might be to instead purchase a standalone Skype for Business Online Plan 2 license and assign it to a account which already has Business Essentials or Premium, further allowing the additional of the add-on licenses.  But that is redundant, as pointed out earlier in this article, as well as more expensive.  For example a Business Essentials license and a Skype for Business Online Plan 2 licenses together cost more than the single Enterprise E1 license does.  In short, if any PBX or PSTN capabilities are required in the environment then an E1 license, plus the desired add-on licenses is the recommended path.  In most cases the Business plans will not be applicable for this reason.


Please understand that Microsoft licensing can be very fluid and change over time so the comments in this article are not indicative of any official support statements from Microsoft or any partners.  The information is simply guidance meant to assist the community with successfully navigating what can be a confusing topic so that meeting devices like IP phones or video conferencing systems can be properly deployed.  As these comments are based on my own understanding of the topic gathered from navigating several different sources of information then some or all of this may be at some point rendered inaccurate or invalid.

By Jeff Schertz

Site Administrator

21 thoughts on “Understanding Office 365 Licensing for Meeting Devices”
  1. Jeff, you should send this to Microsoft because they don’t have a clue how any of this is licensed.

  2. Hi Jeff, Excellent article as usual. Do you mind adding to this article the scenario when customer is using CCE or a hybrid FE for PSTN connectivity?
    Thank you very much

  3. All these licenses make it cheaper to just stay on Prem. We just renewed our EA for 3 years. We stayed with E3 CALs. We cant make a business case for moving to the cloud.

  4. Thanks for this very clear explanation and configuration of the SfB and Meeting Room license requirements.
    I only wish that the Microsoft O365 support had told me this when I was struggling to make our Trio work more than a year ago.
    Using your other guide I was able to get ours to accept meeting requests and join meetings and now have been asked to configure for dial-in/out and Ad-Hoc so this new article is VERY timely.

  5. Really good article. I have some doubts, and maybe you could explain, If I have PSTN Calling, PSTN conferencing is needed to made an ad-hoc conference call? And another question, the PSTN Conferencing license is needed for the endpoint or for the person that sends the meeting invitation?

    1. No add-on licenses are required to create an ad hoc meeting from the device, that is covered in the Plan 2 or higher base license. These licenses all apply to the meeting scheduler, so: the person sending the invite.

  6. Hi Jeff,

    good read.

    For an on prem Skype for Business Enterprise Voice deployment, if we deploy common area VVX handsets with a EV number, what MS licensing requirements/options do they have for EV?

    Users have E3 + Voice CALs. Is that the same requirements for these common area phones?
    Or as an example, could they just have E1 + Voice CALs?

    1. The phone itself doesn’t matter, it’s the type of account you use with it. If you are talking about on-premises Server deployments utilizing Common Area Phone (CAP) accounts then there is no license for these as they are not AD users, only contact; yet using regular user accounts w/ Exchange mailboxes require a license no differently than a regular person’s account. If we are talking about SfB Online then there are no ‘CAP’ account available online and the phone must use a regular user account configuration as detailed in this article. Also as I ‘ve explained the only difference in E1, E3, E5 offerings here are related to bundled Office suite or bundled SfB Add-On licenses, so you can use any of the Enterprise plans. Also CALs are the old license model related to on-premises server deployments specifically.

  7. Is it possible (I’m guessing not) to have a “meeting room” that can be scheduled by all users in the company for Skype+PSTN calls, the invitation to the meeting include all the relevant information to join (Skype & PSTN), but without all users having PSTN calling features (ie. Enterprise licensing)?

    For example, I have a bunch of users that have Business Premium licensing and therefore Skype P2. Great for Skype-to-Skype calling but no PSTN abilities. I don’t need every single user to have their own dedicated PSTN #. I want the “conference room resource” to have a dedicated PSTN number that users get to use when they book the room.

    I feel like nobody does this but I don’t get why. Skype would be the perfect place for us to have it since we use Office365 heavily already and schedule meetings in Outlook to “room mailboxes”. It would be a natural extension to be able to reserve a shared room+Skype call+Skype PSTN # for the meeting all in one go. Needing to license 50+ users to have the ability to include PSTN calling when all you really want is to handle 1 conference call at any given time sure feels like I’m getting ripped off. Who cares who the user is who booked it, it’s 1 concurrent PSTN call. If I need more “capacity” for PSTN calling I should be able to scale that separately from users.

    1. Jason, unfortunately because Audio Conferencing (previously called PSTN Conferencing) and other Skype add-in licenses are user based and not concurrency based then this the result of that model.

      1. Jeff,
        Just so I understand correctly, the only way to allow non-audio-conference-enabled users to utilize a room that IS audio-conference enabled, is to procure and assign an audio-conference license to that user? So essentially all users would need audio conferencing licenses to have a dial-in number present in their calendar invites? Thanks in advance for the clarification.


        1. Correct, the meeting organizer/scheduler requires that the license be assigned to their account so that the additional details can be included in invitations they send out.

          1. Hi Jeff Thanks for the good article. Just to ask a query on the back of Kevins – does thew new Skype Rooms license allow a user to invite 3rd parties to a meeting and invite the meeting room and the meeting room can be the default presenter of the meeting and the audio conf license be assigned to it? Or whats the advantage of skype rooms over a normal skype for business entering a room and signing in on the room pc as the meeting presenter?

          2. The new license is designed specifically for solutions like the Skype Room System/Microsoft Teams Room platform. It’s simply bundling the needed capabilities without the overhead of unneeded features. Inviting a user to a current meeting from the meeting room no additional licenses are required. The Meeting Room license SKU includes the SfB Online Plan 2 license (needed to schedule a meeting or invite others to one) and the Audio Conferencing license (needed to invite a PSTN participant to a meeting).

  8. It should probably be noted that now, there is a Common Area Phone license available in Office 365 that you cna use for Common Area Phones as well as Meeting Room accounts. This brings the cost/complexity of licensing common area/meetings area devices right down. I haven;t run into any limitations using these licenses for meeting rooms yet…

  9. According to Microsft O365/Skype support, this is wrong. They said that the E5 does not include the ability to add PSTN attendees as per your “third secenario”. If you contact me directly, I will give you the Ticket Number. Personally, given the abysmal support from Microsoft, I think you are more likely correct, but it doesn’t work on our SRS and they say it shouldn’t/wont.

    1. I don’t see how that could be the case as the E5 license includes the Audio Conferencing add-in license. The Audio Conferencing license is what allows PSTN participants to join a meeting. In fact the information in that table came directly from a Microsoft support article.

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