T-Mobile US took the wraps off its 5G Voice over New Radio (VoNR) service by launching it in some areas of Portland, Oregon and Salt Lake City for customers with Samsung Galaxy S21 5G smartphones.

The mobile operator plans to expand the VoNR service to additional areas this year.

Vendor partners for the service, which is supported by the operator’s 5G standalone (SA) network, include Ericsson, Nokia, Samsung and Qualcomm.

In 2021, parent Deutsche Telekom teamed up with the four vendors for what it claimed was the world’s first VoNR call on a multi-vendor network.

And last week Zain Kuwait laid claim to the world’s first commercial launch of the technology.

T-Mobile’s VoNR service, which doesn’t include any additional charges, claims to enable slightly faster call set-up times, meaning there’s less delay between the time a user dials a number and when the phone starts ringing.

The service also brings T-Mobile one step closer to leveraging more of its 5G SA network which is a service-based architecture.

T-Mobile launched its 5G SA network two years ago while fellow US operators Verizon and AT&T are still in the process of deploying theirs.

5G SA is heralded as enabling mobile operators to offer more advanced services, such as network slicing and API-based business models, that will in turn create new revenue opportunities.