Feb 9 (Reuters) - T-Mobile said on Sunday it

has started wide-scale testing of its satellite-to-cell service,

powered by SpaceX's Starlink, as the U.S. wireless carrier aims

to eliminate mobile dead zones and extend connectivity to remote

areas.

The beta trial will be free till July, after which the plan

will be included in T-Mobile's premium Go5G Next plan at no

extra cost. The service can be added to all other plans for $15

a month after its commercial launch this summer.

The move could mark a pivotal shift in mobile connectivity,

bridging the gap between traditional cell networks and satellite

technology to ensure seamless coverage anywhere on Earth.

T-Mobile said 500,000 square miles of the U.S., which is

unreachable by terrestrial cell towers, can now stay connected.

The beta launch will offer text service via satellite, while

voice and data features will be added later, the company

announced during the Super Bowl game on Sunday.

Customers who sign up for the trial will get a 33% discount

when the service is commercially launched, the wireless carrier

said.

The service could bolster the company's competitive edge, as

its investments to expand coverage, including in smaller markets

and rural areas, have driven industry-leading net phone

additions in the fourth quarter.

"This is something that nobody else in the U.S. has done,

and one of the big distinctive things this network has is that

it works across almost all smartphones from the last four

years," Mike Katz, president of marketing, strategy and

products, told Reuters.

T-Mobile has been working closely with Apple ( AAPL ) and Google to

"ensure that this experience is integrated directly into their

OS (operating system), and this will be the default satellite

system across both of those phones," Katz said.

The carrier is offering the T-Mobile Starlink service

directly to all wireless users, including customers of rival

telecom firms AT&T ( T ) and Verizon without having to

switch.