Microsoft Teams is the hub for teamwork in Microsoft 365 and the fastest growing business app in Microsoft’s history.  Teams allows free calls to other Teams users, and by adding an additional Microsoft Business Voice licence it enables the ability to call outside of Teams over the PSTN i.e. to any standard telephone number.

But the Business Voice phone system functionality is quite basic and is missing the functionality of a modern unified communications system; for small businesses that require a very limited telephone system and do not have existing telephone numbers to keep then it may meet requirements. In addition a Microsoft Calling Plan is required to provide a bundle of minutes, which can prove rather expensive.

An alternative is to connect MS Teams to CallSwitch2Teams, our feature-rich cloud-based Unified Communications phone system with free calls to landlines and mobiles, or to connect Teams via our Direct Routing and make calls via secure SIP trunk connectivity.

As well as improving on the features of Teams and providing free calls, take advantage of TSI friendly and personal support.  We have over 25 years of supporting business in the UK, from SME’s with a handful of users up to £1.05 bn turnover.  TSI can provide advice on best practices and guidance on how to configure your communications to work for your business.  Our support team are there to help at every step of the way – from managing the sometimes painful process of porting numbres through to training your staff and being there to troubleshoot any problems or answer any questions.


This is a simple, cloud-based solution to take advantage of the features and benefits of CallSwitch, added to M365.

Teams allows you to make business calls while at home, on the road, or in the office from Windows, Mac, iOS or Android, and easily add video and sharing.  By connecting your CallSwitch phone system to Teams every user can make and receive calls over the PSTN outside of Teams – a true enterprise voice solution.  Adding calls and voice to Teams delivers a step-change in user productivity combined with the MS Teams collaboration platform.

CallSwitch2Teams enables the ability to call when and where your users need to.  No hardware is required – a true multi-tenant scalable cloud service, simply use it on a per-user subscription basis.

  • Free calls to landlines (01/02/03 numbers) and mobiles
  • Quick, simple, and low-cost to instantly connect CallSwitch to Teams without buying hardware or sfotware
  • Full featureset of an enterprise grade cloud-based unified communciations phone system combined with the colllaboration of Teams
  • Fully MiFID II and PCI compliant and secure
  • Scalable per-user subscription
  • Contact Centre funcionality, PBX call flows, groups, queues, call recording, and auto-attendant functionality added to Teams, plus a multitude of advanced telephony and UC features

Direct Routing

Direct Routing provides a PSTN solution for the MS Teams Phone System. It allows users to make and receive UK and international calls to, and from, non-Teams users, without needing a hosted telephony system or PBX and offers a cost-effective alternative to Microsoft’s Calling Plan.

By connecting the Microsoft 365 environment to our resilient, geographically diverse pair Microsoft approved Session Border Contoller (SBC) calls can be made to the PSTN network via SIP.  Or to put it another way, you can make a phone call from Teams!

Enhance the limited phone system of Teams with additional features including free call recording to make it you fully integrated phone system with PSTN calling.

  • No onsite hardware required
  • Secure SIP trunk connectivity
  • Real-time location-based routing
  • Real-time voice quality monitoring
  • Automated provisioning
  • Available from 30 day terms

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