Most organizations already run their meetings and messaging in Microsoft Teams or Webex, so adding calling to the same app is a natural next step. Doing it well means connecting the platform to a VoIP phone service that carries calls to and from the public phone network, replaces aging business phone systems, and keeps the numbers your business already uses. This guide covers how that integration works, the options available for each platform, how to choose between them, and the steps to get from decision to rollout.
Microsoft Teams and Webex both give people a place to make and receive calls, but on their own they don't reach the outside phone network. That connection is what a VoIP phone service provides. Voice over IP, or VoIP, carries calls over the internet rather than a traditional phone line, and the service sits between your calling platform and the public switched telephone network (PSTN).
In practice, the service supplies the pieces the platform doesn't: phone numbers, call routing, number porting from your current provider, and the in-country licensing and compliance that let you make regulated calls in each market. It helps to separate two kinds of call here. Calls between colleagues inside Teams or Webex already travel over the platform at no extra cost. Calls to and from external numbers, like a customer's mobile or an emergency line, need the VoIP service to reach the public network. Bringing the two together means one system handles both, which is how a hosted VoIP setup replaces a separate business phone system or an old business landline.
The appeal is consolidation. Instead of a desk phone tied to a PBX and a separate app for meetings, people get calls, meetings, and messaging in one place, on any device. Moving from a legacy PBX to a VoIP telephone system that lives in the app brings a few knock-on benefits:
Microsoft Teams supports three ways to connect calling, and the right one depends on how much control you want and where you operate.
Microsoft Calling Plans
With Microsoft Calling Plans, Microsoft supplies the numbers and calling directly as part of your subscription. It's the simplest option, suited to smaller or single-country footprints in the markets where Calling Plans are available. Coverage and number features vary by country, so it fits best when your needs are straightforward.
Operator Connect
Operator Connect lets a certified operator connect its VoIP service to Teams. You choose a provider from within Teams, and numbers are managed in the Teams admin center, with no session border controller for you to run. It's a middle ground, with more provider choice and wider coverage than Calling Plans and none of the overhead of running your own connection.
Direct Routing
Direct Routing connects Teams to a carrier through a session border controller (SBC). It offers the most control and flexibility, including coexistence with existing phone systems during a migration, and it reaches countries the other models may not. You can run the SBC yourself or take it as a managed service, common for businesses that want the flexibility without the in-house work.
Webex Calling offers a similar spread, from Cisco handling everything to a model where you keep more control.
Cisco Calling Plans
Cisco supplies calling and numbers directly in supported countries. It's the most hands-off option, suited to simpler deployments where Cisco's coverage matches where you operate.
Cloud Connect
With Cloud Connect, a certified provider connects its VoIP service to the Webex cloud, so you get provider choice and broader country coverage without an on-premises gateway. Numbers and calling come from the provider and are managed through Webex.
Premises-based PSTN (Local Gateway)
Premises-based PSTN connects Webex Calling to a carrier through an on-site gateway, known as a Local Gateway. It's useful when you need coexistence with existing equipment, or have specific local requirements that call for on-premises control.
No single model suits everyone, and the choice comes down to a handful of factors:
As a rule of thumb, a certified provider model (Operator Connect or Cloud Connected PSTN) fits when you want coverage and simplicity, while an SBC or gateway model (Direct Routing or a Local Gateway) fits when you need maximum control or coexistence with existing systems and older VoIP systems. Many organizations run a provider-connected model in most countries and Direct Routing where a specific requirement calls for it, which is one reason it helps to work with VoIP providers that support several models.
A smooth rollout depends on groundwork. Before connecting anything, line up:
1. Platform licensing
The Teams or Webex licenses that include calling for each user who needs it.
2. A number and site inventory
Every phone number, location, and country in scope, so nothing is missed at cutover.
3. Network readiness
Enough bandwidth, quality of service (QoS) settings that prioritize voice, and reliable Wi-Fi where people roam.
4. Devices
Certified IP phones, headsets, and meeting room phones that work with your platform, since certified IP phone systems head off call-quality and support surprises later.
5. Legacy lines
Anything still on a business landline, such as alarms, elevators, and fax machines, which may need a separate plan or a spell running VoIP and landline side by side.
6. Emergency calling
Accurate emergency locations and routing for both office sites and remote users.
Match the model to your platform, your country footprint, and your team's capacity to manage infrastructure. This is where the earlier decision, provider-connected versus SBC or gateway, gets locked in, along with the VoIP providers you'll work with.
Assign calling licenses to the users who need them, then confirm each site is ready on bandwidth, QoS, and devices. Fixing network issues now is far easier than chasing call-quality complaints after go-live.
For provider-connected models, you authorize your chosen provider in the Teams or Webex admin center. For SBC or gateway models, you configure and connect the session border controller or local gateway to the carrier. Either way, this is the point where your VoIP system starts carrying real calls.
Port your existing numbers from your current provider, or assign new ones, and keep the old services active until every port completes so no one loses service mid-migration.
Set up call routing, auto attendants, and call queues or hunt groups, then configure emergency locations for both fixed sites and remote users so emergency calls reach the right responders.
Start with one team or site to validate the setup, train users on the new calling experience, then roll out in phases rather than switching everyone at once.
Plenty of businesses run both platforms, often after a merger or because different regions standardized on different tools. You don't have to force everyone onto one. A single VoIP phone service across both Teams and Webex keeps numbering, routing, and support consistent, so the caller experience and your admin overhead stay the same whichever platform a team uses.
The provider you choose shapes call quality, coverage, and how smooth the migration feels. Weigh VoIP providers on:
This is where Pure IP fits. As a certified provider for Microsoft Teams and Webex Calling across Operator Connect, Direct Routing, and Cloud Connected PSTN, with numbers and regulated calling across a large global footprint, Pure IP delivers the VoIP phone service beneath your platform and handles the porting, compliance, and support that hold an integration together.
Bringing voice into Teams or Webex gets much simpler once the decision is broken down: pick the model that matches your platform and footprint, do the groundwork on licensing, network, and numbers, then roll out in phases. Get those right and calling becomes one more thing your team does in the app they already use.
If you're planning an integration and want help choosing a model or scoping the countries involved, talk to our team.
How do I get VoIP phone service for Teams or Webex?
Choose an integration model and a certified provider that fit your platform and countries. From there, assign calling licenses, connect the service to Teams or Webex (through the admin center, or an SBC or gateway), then port or assign your numbers. The step-by-step section above covers the full sequence.
How much does VoIP phone service cost?
A VoIP phone service usually has two cost components: the platform calling licenses from Microsoft or Cisco, and the calling service from your provider. What you pay depends on the countries you need, call volumes, user numbers, whether you run an SBC or gateway, and any migration or managed services. Because those variables differ so much between businesses, a quote based on your own footprint beats a headline per-user price.
Is there a free VoIP service?
Free VoIP exists for app-to-app calling: people on the same platform can call each other in Teams or Webex at no extra cost, and many consumer apps offer free calls between their own users. Calling regular phone numbers is different, because it means reaching the public network, which requires a paid calling service. For a business that needs to call customers, suppliers, and emergency lines, a paid VoIP phone service is what makes that possible.