Hello Readers, I hope you are well.

This is a very quick post to show you how to enable extension dialing in Microsoft Teams.

The use case should be fairly obvious. I will also add that there are better ways to reach users or service numbers than extension dialing. Dial-by-name, being the one I would recommend in most cases. But what if you need to enable it so users can dial 3 or 4 digit numbers to reach people or a call queue. It’s likely they want to do that because that’s what they were used to in the previous system. The last thing you want to do is introduce friction when migrating to a new system when you want to ensure there is adoption.

As I said, I would recommend ensuring that users are aware that they can easily search for users by name when calling them or initiating a transfer. Some will hopefully see the logic and start using the new way. But you should also know that it is possible to give the users that are used to it, a way to keep doing it the way they did it before.

My example is for a very specific use case and came from a question I received from someone through social media. They asked if it was possible to add an extension number to a call queue in Teams via Direct Routing. I said it was of course possible to assign an on-premises telephone number to a call queue. But they wanted to use an extension number in addition to the full telephone number.

I said that it was possible to get the users to dial the call queue by name. Just use the SIP address and that will result in a call to the call queue.

That will show in your call history as the display name you gave your resource account.

You can even add the address to a contact if you call it frequently.

He said that’s great, but the users want to dial the extension they used in Skype for Business. How do it do that?

If you read my blog, you’ll know I wrote a post on how to assign a direct routing number to a resource account. I tried, just to see what would happen, to add an extension to to an existing resource account in addition to the telephone number.

Set-CsOnlineApplicationInstance -id
-OnpremPhoneNumber "+441635776443;ext=6443"

To my surprise, the Skype Online PowerShell module took the above command without error. However, I ran repeated Get-CsOnlineApplicationInstance -id
ResourceAccount@domain.com and the Phone Number attribute never updated to show the extension number. I didn’t expect it to, but wanted to make sure.

So I thought, in Skype for Business, you would do this using a normalization rule. So, knowing that the Teams Admin Centre now has dial plans, that’s where I went next.

How to do it

Open the Teams Admin Centre and expand voice and go to Dial Plans

Now click on the Global Dial Plan (or your custom dial plan) or create a new one to assign to users.

Under Normalization Rules click Add

Now just fill in the form with the details of your use case.

Give it a name

A Description is that is useful

Then a condition match

And the result

My rule was to take a 4 digit number, starting with 6 and add a prefix which was +44 (the country code) 1635 (the area code) and the last two digits before the last 4/extension number. Effectively translating the extension number into a standard (E.164) format.

You can even test the rule before you save it to see if you get the result you’re after.

If it looks good, save it. Now you will see your rule listed.

Now wait about 5 minutes and you can test it in Teams. In my case, as I said, I used it to create a 4 digit dialing rule that mapped to the direct routing DDI I had assigned to a specific resource account that was assigned to a call queue.


Dial the 4 digit number using the dial pad in Teams. That will normalize after you hit dial and it will route to the full e.164 number for your resource account and place a call to the call queue. In my case, Customer Services.

Of course, I used it for a very narrow use case. If you have a block of numbers and you want to enable extension dialing for all users, this method will work. You can narrow it down further if you have a single MSN to route/translate. I could have used the actual 4 digit extension as the starting digits. This is often used when you want to map an old extension to a new DDI range or new number.

And that’s all folks! Hope it was sueful

For more information about Normalization Rules in Teams you can read about it on the Microsoft Docs page.