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Link your business phone system to Microsoft Teams

Extend your business phone system into Microsoft Teams with Manx Technology Group. A converged system allows you to extend the use of your phone system outside of your office and into your Microsoft Teams environment. Staff who are using Teams desktop, web or the mobile app – can make and receive phone calls as if they were in the office. Calls arriving to your business PBX can be routed to Teams users.

With recent events surrounding coronavirus and the need for social distancing, many organisations have introduced remote working policies for their staff. While some businesses can use VPN, VDI (Virtual Desktop Infrastructure) or an IP phone system to enable remote working; many organisations will be limited in what options available.

Quick Summary

  • Microsoft Teams can operate as a fully functional phone system.
  • Teams can scale to many thousands of users.
  • For businesses with an existing system, we can link your business PBX to Microsoft Teams.
  • Users can dial between systems.
  • Teams is a fantastic video conferencing system.
  • Calls arriving into your business phone system can be routed to Teams users, and vice versa.
  • Options exist for cloud phone systems, on-premise (office) systems and legacy phone systems.
  • Teams phone system requires a compatible O365 license.

While cloud services such as Office 365, e-mail and collaboration apps such as Microsoft Teams make it easier to work remotely – the telephone remains a crucial tool for any business.

Access the business phone system from home

Several methods would enable your staff to access the business phone system from home:

  • Cloud phone system. For businesses who have a hosted system – staff members can use a Softphone, Mobile App or bring an IP Handset home. Several of our customers who use 3CX have done this to enable remote working.
  • IP phone system. With an on-premise IP phone system installed in your office; staff members may be able to use a software phone or handset from home (but this may require feature licenses).
  • Divert. Not an optimal solution, but business DID (Direct inward dials) can be redirected to staff mobiles or landlines.

What about Microsoft Teams?

Teams phone system
Teams is a fully featured phone system. If you have an existing system, we can link the two together.

MTG customers who use Microsoft Teams have found the transition to remote working more accessible, thanks to the use of chat, video conferencing and the collaboration functionality that Teams offer.

Many, however, do not know that Teams itself can operate as a fully-functional business phone system, from within the same Microsoft Teams app. Users can make and receive calls, it supports voicemail, and businesses can benefit from call queuing and auto-attendants.

Teams has experienced immense growth as users recognise the value it brings to business, in part due to the Coronavirus pandemic.

How do I enable phone system support for Teams?

To enable phone system support, it is a simple enhancement to your Office 365 license.

There are some requirements:

  • You must have a valid Office 365 subscription (Business Essentials, Business Premium, E1, E3, E5).
  • You will need a Microsoft Phone System license (£6.00 per month).
  • You can then select from a range of calling plan (Domestic and International), that provide each of your users with a phone number and calling functionality.

Once the license has been applied (takes a few moments), and numbers selected – your Teams users can start dialling in and out.

Can I link my phone system to Microsoft Teams?

If you would like to extend your phone system into Microsoft Teams, there are several ways this can be achieved. The expansion of your phone system may be temporary (during COVID-19) or a preface to a full migration later.

The different methods are outlined below (depending on your existing system):

a) IP phone system

  • Your IP phone system must support SIP trunks.
  • You would need to configure a domain (i.e. customer.voice.mtg.im) in your Office 365 tenancy.
  • MTG would create routing policies on our SBCs to/from your Office 365 tenancy.
  • DDI numbers would be allocated to your users within Teams.
  • A SIP trunk is configured from your phone system to the MTG operated SBC in Azure.
  • Dial-plans are created that allow calling from Teams, via the SBC, to your phone system, and vice-versa.
  • Teams users can be included on inbound call queues and hunt-groups on your business phone system.
Microsoft Azure Logo
MTG use Microsoft Azure and Ribbon SBCs to provide seamless integration between Teams and your phone system

Example phone systems that can be linked to Teams include:

  • Asterisk
  • Avaya
  • 3CX
  • Cisco Call Manager
  • Mitel
  • Panasonic
  • ShoreTel

A SIP trunk will be required and following the steps above.

b) Cloud phone system

If you have a cloud PBX or similar hosted system, the steps are very similar to (a). As a cloud system affords some flexibility, if Teams is a consideration, it may be that a better option is to consider a full migration away from your existing vendor to Microsoft Teams.

c) Alternative to a & b

An alternative to the SIP trunk method mentioned in (a) and (b), we can also use SIP registrations. Our SBC can register as an extension on your phone system. When someone calls the extension, the system calls our SBC and the user on Teams. When the user on Teams dials out, the SBC routes it out via their extension on your phone system.

d) Non-IP or Legacy phone system without SIP

  • MTG setup Microsoft Teams with phone system licenses.
  • Each user is allocated a DID/DDI.
  • You can divert your extensions or numbers to the corresponding numbers/extensions in Teams.
  • MTG can program a dial-plan within Teams that allows short-code dialling to extensions that remain on the legacy system.
  • Teams users dial-out via the MTG SBCs.

Do I need to configure it?

You can – however – this is a service we provide. Direct Routing and the various functionality required to enable voice integration requires a good knowledge of Powershell and the mechanics of Azure/Skype/Teams. As part of our service, we can guide you through the process or manage the change on your behalf.

How will it appear to the users?

No different.

Your users will use the Teams app to message, share documents and have video calls.

  • When the user wants to dial-out externally, they do so from within Teams.
  • If the user wants to dial a user who is on the business phone system, they do so within Teams.
  • Calls incoming on the legacy system can dial the users on Teams.
  • Users can all benefit from Teams voicemail, voicemail transcriptions, etc.

What are the benefits of using Teams as a phone system?

Microsoft Teams
Teams is a fantastic tool that enables remote-working, video and audio, screen sharing and collaboration
  • Scalability. Teams will scale to many thousands of users with a month-by-month commitment.
  • Calling plans. Domestic calling plans include bundled minutes which reduce calling costs.
  • Simplicity. With Microsoft 365; apps, e-mail, Sharepoint and voice can be handled through a single subscription.
  • Inbound numbering. National and international phone numbers can be routed to Teams instantly and seamlessly.
  • Unified communications. Staff benefit from a single app for voice, video, chat and document sharing – on mobile, desktop, tablet and the web.
  • Avoid significant Capex. Gracefully extending your system into Teams extends the life of your business system yet enables your staff to benefit from the latest technology.


Don’t forget – Microsoft has some great incentives available for charities and non-profits. Microsoft 365 and Teams is the perfect tool for charities! Speak to us to find out more.

Find out more

If you would like to discuss how Microsoft Teams can be used in your business, how MTG can help your extend your telephone system into Teams or would like to learn more; please contact sales@mtg.im, call +44 1624 777837 or select ‘Request a Quote‘ on our website.

Manx Technology Group is a Ribbon Partner – so our team can implement the full range of Ribbon cloud, virtual and on-site SBC solutions to enable seamless calling between your business phone system and Microsoft Teams.

What about Isle of Man numbers?

Isle of Man numbers are not yet supported on Microsoft Teams however Manx Technology Group is a Direct Routing partner with our own SBCs (Session Border Controllers) hosted in Azure.

What does this mean? As we operate our own SBCs that are directly-connected to Teams and Azure, calls can be redirected or routed from your phone system, to our SBCs, without incurring and telephone costs. We are also able to provide numbering from 100s of different countries and a wide range of UK geographic, non-geographic and freephone numbers.

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Joe Hughes is the CEO of Manx Technology Group. Joe has a background in software development, information security, networks, datacentres and enterprise IT.

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