Why can’t I use my current user telephone number as a service number?
Published Apr 12 2017 06:33 AM 2,773 Views

Great question. Before I provide an answer - let’s first start off with a brief overview and basic terminology. If you have ever requested a new PSTN Number in Skype for Business Online, you may have noticed that you can request 2 types of numbers, detailed below.


Basic Terminology

  • User Number – a telephone number that can be assigned to a user.
  • Service Number – a telephone number that can be assigned to a service. Skype for Business Online provides the following services: Dial-in conferencing, Auto Attendants, and Call Queues.

Service numbers look the same as user numbers, but the architecture behind them is different to support a high number of concurrent calls.
For more information about, refer to the Services Numbers vs User Numbers blog article.
With this terminology in mind, let’s describe a scenario where you can run into an issue.


Let’s say you ported a telephone number into Skype for Business Online. It is a really cool number that is easy to remember e.g. xxx-500-1111. Now you attempt to assign that number to an Auto Attendant or a dial-in conferencing bridge. But wait, the Admin portal won’t let you. What? What’s going on? We don’t allow a ‘user’ number to be assigned to a ‘service’. We only allow ‘service’ numbers to be assigned to a service – for example an Auto Attendant.

Ok – what’s next? If it is a US based number, you can assign that telephone number to a service. Although, an extra step is required.


To use that telephone number for a service, we must first reclassify the ‘user’ number as a ‘service’ number. To start the conversion process, you simply need to create a service request. Again, the ability to reclassify a user number to a service number is currently only available in the US market only.


How do I get the number converted to a service number?

  1. Open a general service request in the Office 365 Admin Center. You may also open a support case with Microsoft Premier.
  2. After the conversion is completed, we ask the customer to verify the conversion, and close the service request.

How long does it take to do the conversion?
We don’t provide an SLA for converting the number, but it will mostly likely take a few days to complete the request. It is important to note, that during the conversion process, the number will be unavailable for a period of time, and you cannot see the number in the tenant. This is expected.

What if my number is outside of the US region?
You can assign a new service number that is provided by Microsoft.


Is there anything I can do to avoid this conversion process?
Yes. When a number is initially ported into Skype for Business Online, you can specify that the number is ported in as a ‘service’ number. The port request must happen separately from other types of numbers.

This topic is also discussed in our Cloud PBX with PSTN calling training: http://aka.ms/sa-pstn.

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