How to integrate PBX with Microsoft Teams

How To Integrate Your PBX With Microsoft Teams 

If you want to use Microsoft Teams as your phone system (I.e., for making and receiving external calls), you can certainly do so. 

And if you’ve already got a PBX in place, that you wish to re-use, you can now integrate your PBX with Microsoft Teams. 

Why keep the PBX? 

Common reasons include: 

  • Sweating the asset: you paid good money for it once upon a time and it still works okay 
  • Long-term contract: you’re still paying for PBX functionality 
  • Industry legislation: you can’t move your calling into the cloud for data or privacy reasons 

So, if you’re keeping your PBX and need to integrate it with Teams, this blog post details the steps you need to take to set up various types of integrations. 

For the purpose of this blog post, by “PBX”, we’re referring to an on-premises PBX. If you run a cloud PBX, you can now integrate most cloud PBXs by visiting the Teams app store and searching for your provider. 

Integrate cloud PBXs with Microsoft Teams

What PBX features does Microsoft Teams have? 

You can enable the following PBX features without needing to integrate your own PBX: 

  • Call transfer 
  • Call forward 
  • Call pickup 
  • Caller ID 
  • Device switching 
  • Secondary ringer 
  • Distinctive ring alerts 
  • Shared line appearance 
  • Call blocking 
  • Busy on busy 
  • Presence-based calling routing 
  • Auto attendant 
  • Call queue 
  • Voicemail 
  • Music on hold 

To access these features, you need to buy a Microsoft Teams Phone license. On top of that, you need a calling plan of some sort. This might be Microsoft Calling Plan, Direct Routing, Operator Connect or another type of PBX integration

If you need further functionality, you will need to integrate your PBX, be it on-premises or cloud, to Teams. 

Option 1: Keep your PBX long-term and just want to surface its calling features within the Teams client

This option is attractive if you have recently purchased a PBX system (3CX for example) and do not want to pay the Teams Phone Standard License premium on top of your existing Microsoft Licensing to unlock the native dialpad. 

Instead, you connect the softphone client to Teams as a Teams App and use the PBX providers software to make and receive calls within Teams.  

The pre-requisite is that your PBX vendor can support this both with their client softphone software and your call manager system.  

The alternative, if you still want to pursue this route, is to use a third-party PBX connector that offers both the phone connectivity between Teams and your PBX as well as the softphone client software to install into Teams itself. 

Unfortunately, Callroute does not offer this type of integration. However, there are other integration providers that do, such as Call2Teams. 

Call2Teams PBX integration with Microsoft Teams

Option 2: Retire your aged PBX in favor of more SaaS-based cloud communication platforms

When researching connectivity options there are usually two main problems that need to be addressed: 

  1. How can users keep their existing numbers? 
  1. How can we manage the transition between PBX and Teams? 

For users to keep their existing numbers, your phone line provider (carrier) will need to be connected to Teams.  

Your phone lines could still be physically connected to your office and PBX and as a result, you will need to provide connectivity from your office to Teams.  

To address this issue, you have several options available to you: 

Do you purchase a new cloud-based SIP trunk service and terminate it directly into Teams using Operator Connect or Direct Routing?  

If you choose this option, you will need to initiate a number port from your current carrier to your new provider.  

This can cause delays and increase the complexity of migrations as well as offering no integration between Teams and your PBX users that remain on your current system. 

Do you approach your existing phone provider and enquire if they offer their own Teams Direct Routing solution?  

If they do, it will be a separate product to your existing phone line, and while you don’t need to initiate a number port, there will be a requirement for a product switch with your carrier on a number-by-number basis.  

Like number porting to another carrier, being on a separate product even with the same carrier, you will lose integration between Teams users and your PBX users, especially if you rely on extension dialing. 

Option 3: Connect your PBX gateway to Teams and use the existing phone line service as-is

This way you are in control of where numbers route, to your PBX or to Teams.  

In addition, you can configure internal extension routing between Teams and your PBX, integrating them for a more joined-up calling service which solves your second problem of migration coexistence. 

However, it is very likely that your PBX gateway is not supported for Teams Direct Routing. If your gateway is not certified, you face a decision. Do you purchase your own certified SBCs, or look for a connector alternative? 

With Callroute, you can connect your existing on-premises or cloud PBX gateway to our cloud SBCaaS regardless of its certification and use our certified Teams gateway to connect to Teams. 

This means that you will be fully supported by Microsoft, and you will be able to connect your existing PBX and phone lines to Teams without purchasing any additional hardware. 

PBX integration with Microsoft Teams via Callroute

In this topology, you will continue to use your phone lines connected to your PBX and you will be able to easily move users from your PBX to Teams, maintaining their direct dial number and internal extension so that users still present on your PBX can call your Teams users. 

If your end goal is to remove your PBX when migration is complete, you can simply turn off your PBX call manager. In this instance, you may want to also remove your on-premises gateway. You can do this by converting your connection to Callroute from BYOSBC to Bring Your Own Carrier (BYOC).  

With BYOC, Callroute connects directly to your carrier from our cloud, meaning you can decommission all on-premises reliance without having to perform a huge migration project again in the future. 

How to integrate your PBX with Microsoft Teams using Callroute 

Connecting your PBX gateway to Callroute is straightforward.  

Your PBX gateway will need to support the SIP protocol and have a static public IP address assigned to it, either directly or via a NAT based firewall (recommended). 

Provided your system can support both these pre-requisites, initial setup should not take long.  

Within Callroute, you’re going to be using the Bring Your Own SBC (BYOSBC) feature.  

This allows you to connect Callroute downstream to your main telephone line service.  

Head over to the Carriers section of our portal and click the “Connect an SBC” button. 

Connecting an SBC to Microsoft Teams

You will need your PBX public connectivity information to hand to complete the settings in the modal popup. 

Connecting an SBC to Microsoft Teams
  • Label your PBX gateway connection as you see necessary. 
  • Choose your signaling protocol for your SIP traffic.  
  • We support both Secure SIP (TLS) and insecure SIP (UDP). If you want to use TLS, you will need to install a public SSL certificate on your PBX gateway. Self-signed is not supported. 
  • Then enter your PBX gateway’s public IP address. Or, if you’re using DNS, it’s fully qualified domain name that is resolvable public DNS along with its SIP signaling port (usually 5061 for TLS or 5060 for UDP). 
  • Choose whether your gateway will respond to SIP Options. 
  • Finally, enter the public IP address(es) of your media and SIP interfaces to open our firewall to receive traffic from your system. 
  • Press Save. 

Your connection will then show under the “My SBCs” section on the Carriers page in Callroute. 

Viewing SBCs and PBXs connected to Microsoft Teams

Click the “Configure” button. 

From the configure page, click “View Configuration” and this will show you the connection information you need to set up your PBX gateway. 

PBX gateway config for Microsoft Teams

Next, configure your PBX gateway to connect to Callroute using the information above. You will need to consult the administrator guide relating to your own equipment. 

Next in Callroute, you will need to add the number range relating to your Teams users. You can do this by going to the Numbers section of the portal and clicking “Add a Range”. 

Add a PBX number range to Microsoft Teams

Enter the first number in the range and how many numbers are contained in that range. Then select your PBX gateway from the list of carriers and press Next. 

Now you need to set your default inbound route for calls received by Callroute. Select Microsoft Teams and press Save. 

Configure a PBX number range in Microsoft Teams

And that’s it from a basic setup perspective.  

All that remains now is for you to use our portal to assign Teams users their phone numbers, then modify your PBX gateway routing table to route all calls to these Teams user numbers to the Callroute SIP trunk you created. 

For more detailed information, please view our knowledge base:  

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Intermittent Microsoft Teams calling issues reported globally. This issue appears to be affecting all Microsoft customers worldwide. Microsoft are currently investigating the issue. All Callroute systems are fully operational. More information will be provided as soon as possible.