Uncategorised , | 2017/04/07 at 2:35pm

Microsoft PSTN Conferencing Savings

Since Microsoft PSTN Conferencing was released on September 2016, we’ve seen steady take up of the offering – particularly if you were a Skype for Business Online user already. Prior to this announcement there was no way to get dial in numbers for a Skype for Business Online meeting unless you:

  • Assigned an Audio Conferencing Provider (ACP) for Skype for Business Online – typically Intercall, PGI, others
  • Deployed an on-premises Skype for Business Server environment and provisioned voice circuits and other infrastructure to facilitate this
  • Deployed Skype for Business Hybrid so you could have some users located in the cloud and some located in an on-premises server and the latter users would have PSTN Conferencing services enabled

Now with Microsoft delivered PSTN Conferencing, companies can simply license their users for PSTN Conferencing natively in the cloud without using an ACP. ACP was a little clunky, and billing was done separately from Microsoft and came directly from the provider. Typically, these providers charge per cent per minute for both tolled and toll-free numbers and I’ll explain how this works.

Tolled numbers are your standard dial in numbers – it’s a little misleading, as tolled numbers are your normal tolled numbers that an attendee would dial locally and incur a cost (even if it is just a local call). Tolled numbers in the Microsoft parlance are not charged on a per cent per minute basis – and is likely where most of your users will dial in from by finding a local number that suits them. Tolled numbers are NOT charged on a per cent per minute basis, it’s all you can eat on a per user basis. You simply license the user for PSTN Conferencing and if they are using tolled numbers (in over 90 countries) then there is no additional charges.

Toll-free numbers are your typically 13, 1300 and 1800 numbers that you would dial today. These toll-free services are charged at PSTN Consumption rates and are on a per cent per minute per attendee basis.

PSTN Consumption provides the following additional scenarios for PSTN Conferencing users:

  • Provides dial in to PSTN conferencing meetings using toll-free dial-in phone numbers.
  • Enables dialing out from a PSTN conferencing meeting to add someone else from anywhere in the world.
  • Enables dialing out from a PSTN conference to your mobile phone with the Skype for Business app installed.

Dial-out capabilities mean that the organizer of the meeting is able to dial in participants using PSTN numbers – e.g. a client mobile phone number or their deskphone.

PSTN 1 PSTN Conferencing enables dial in coordinates in Skype Meetings

You can also set a default conferencing number on a per user basis – so if you have staff in Perth for example, you can set their default conferencing number to be a Perth number at no extra charges.

PSTN Consumption needs a pre-commitment (preloading) of credit either via Credit Card or Purchase Order in order to set up a ‘bucket’ of funds available for the above purposes, particularly if you are using a toll-free number. The PSTN Consumption rates are here. You’re looking at Table 2 for AU customers that have tenancies provisioned in Australia.

Suggested funding amounts are here, and relevant for most Australian businesses:

PSTN 2 Recommending Funding Bucket Amounts

You can also auto-recharge your PSTN Consumption bucket when it gets to the Trigger amount, similar to any eTag or eToll system.

Service Numbers

Service Numbers perform important functions in Skype for Business Online – they can be assigned to things like Dial In Conferencing, Organisational Auto Attendants and Call Queues (for those of you using Cloud PBX) – so it’s not just relevant to PSTN Conferencing.

When you first establish PSTN Conferencing, you’ll have an array of numbers to use. These numbers are shared in a sense with all Microsoft customers globally. The numbers are shared, but your conferences are obviously unique to your environment.

PSTN 3 Shared Numbers in PSTN Conferencing

Service Numbers can also help provide dedicated conference numbers that are specific to your tenant and are only used by you or your end users. Below is a list of service number types/areas available in Australia. For example, if you are doing a lot of business in Perth or need a dedicated local number in Perth, you have the ability to obtain a service number there. The number is randomly allocated from a pool of numbers that Microsoft has available, you can’t select or choose the number you are given.

Cost Comparison

I’ve worked with a number of customers to determine existing indicative numbers and spend:

Customer 1

40 users with Telstra Audio Conferencing Access – with 5 hosts

Telstra charges $0.20 per participant, per minute on their Business conferencing plan:

At 6 conference calls per week with 6 participants at 60 minutes per conference = $432 a week, $5,184 a year. In a wider organisation this is also probably on the low side.

Let’s map this out in Skype for Business PSTN Conferencing:


Customer 2

1000 users with Telstra Audio VMR Access – with 35 hosts

35 Conference Rooms with a total spend of $24,000 a year – limited capacity of up to 50 per VMR. Note that with Skype for Business Online, we can have 250 participants maximum in a conference call, and look to Skype Meeting Broadcast if you need more scale than this.

Now let’s map that out in a Skype for Business scenario!


So as you can see, we can extend conferencing to five times the amount of hosts and still save $12,000 a year! Pretty compelling stuff.

If you want further information to explore PSTN Conferencing and Cloud PBX, please reach out!

Stuart Moore
Co-founder and CTO
Insync Technology – www.insynctechnology.com.au
+61 7 3040 3603