Getting Skype for Business service phone numbers

In addition to getting phone numbers for individual users from Office 365, it’s also possible to search and acquire toll or toll-free phone numbers for services such as dial-in conferencing (for conference bridges) and auto attendants which are called service numbers. Service phone numbers have a higher concurrent calling capacity than user or subscriber phone numbers. For example, a service number can handle 100’s of calls simultaneously, whereas a user's phone number can only handle a few calls simultaneously.

Important: PSTN Consumption must be set up first in order to acquire toll free numbers.

You have two ways of getting service numbers so you can use them with Skype for Business:

  • Get new numbers from Office 365 Skype for Business.

  • Port or transfer your existing numbers from your service provider or phone carrier.

    Note: When you transfer your service numbers, it is highly recommended that you contact Microsoft support to ensure the higher concurrent calling capacity is considered and configured correctly.

Get new service numbers

  1. Sign in to Office 365 with your work or school account.

  2. Go to the Office 365 admin center > Skype for Business.

  3. In the left navigation go to Voice > Phone numbers >Add then click New service numbers.

    IMPORTANT: For you to see the Voice option in the left navigation in the Skype for Business admin center, you must first buy at least one Enterprise E5 license, one Skype for Business Cloud PBX add-on license, or one Skype for Business PSTN Conferencing add-on license.

  4. On the Add new service numbers page, use drop downs to choose:

    • Country/Region

    • State/Region

    • City

  5. Under Quantity, enter the number of phone numbers that you want for your organization and click Add to create a reservation. You have 10 minutes to select your phone numbers and you if you take more than 10 minutes the phone numbers will be returned to the pool of phone numbers.

    Note: You can see the number of phone numbers which is based on the number of licenses listed next to Total user number your can acquire.

  6. You can click Show numbers to see the full list of phone numbers. This is helpful is you don't want to select a specific phone number in the list.

  7. Select the phone numbers you want and then click Acquire numbers.

    Important: You can acquire more phone numbers than you have licenses. To determine how many phone numbers you can acquire, take your number of licenses, add 10 percent of the number of licenses, and then add 10. For example, if you have 100 PSTN Calling licenses, you can reserve 120 phone numbers, assuming that you have not already acquired some phone numbers for those 100 users.

Assign service numbers

Once you've gotten your service numbers, these numbers can then be assigned to a dial-in conferencing bridge. To do this, see Assign or unassigned toll and toll-free phone numbers to a dial-in conferencing bridge.

Port or transfer existing service numbers

If you want to transfer service numbers from your current service provider or carrier, you need to manually submit a port order to Microsoft. You have to submit separate port orders for each type of service number (toll vs toll-free) that you will be transferring using a Letter of Authorization (LOA). In the Letter of Authorization (LOA), you must select correct type of service number. When contacting Microsoft support, please make sure you specify that you are transferring a service number (and not a user or subscriber number) or the concurrent calling capacity may not be enough to handle call volumes. If you want to know more about submitted a port order request, see, Manually submit a port order request

When you are looking for and getting phone numbers for your organization, you can get more phone numbers than you have assigned licenses. But this depends on the types of phone numbers and types of licenses you have bought and assigned.

Note: If you need to get more telephone numbers than this, please contact Contact Office 365 for business support - Admin Help.

Here's the type of phone number

How do you get the total phone numbers?

Here's an example

User (subscriber) number

The number of phone numbers is equal to the total number of Domestic + Domestic and International Voice Calling plan licenses multiplied by 1.1 + 10 additional phone numbers are given.

If I have 50 users in total with either Domestic and Domestic and International Voice Calling Plans, you can acquire 65 phone number (50 x 1.1 + 10).

Toll service number

The number of phone numbers is equal to the total number of Cloud PBX + PSTN Conferencing licenses and uses the following:

  • If there are <30 licenses then 3 telephone numbers are given.

  • If there are 31-50 licenses then 5 telephone numbers are given.

  • If there are 51-1000 licenses then 15 telephone numbers are given.

  • If there are 1001-9999 licenses then 25 telephone numbers are given.

  • If there are 10,000+ licenses then 50 telephone numbers are given.

If you have a total of 51 Cloud PBX and PSTN Conferencing licenses you can get 15 toll service numbers.

Toll-free service number

The number of phone numbers is equal to the total number of Cloud PBX + PSTN Conferencing licenses and uses the following:

  • If there are <30 licenses then 3 telephone numbers are given.

  • If there are 31-50 licenses then 5 telephone numbers are given.

  • If there are 51-1000 licenses then 15 telephone numbers are given.

  • If there are 1001-9999 licenses then 25 telephone numbers are given.

  • If there are 10,000+ licenses then 50 telephone numbers are given.

If you have a total of 1001 Cloud PBX and PSTN Conferencing licenses you can get 25 toll-free service numbers.

Important: PSTN Consumption Billing is required to reserve and use toll-free phone numbers.

See Also

Emergency calling terms and conditions

Skype for Business Online PSTN services use terms

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