Edward C. Baig

USA TODAY

NEW YORK—Comcast is set to go mobile.

The cable and Internet provider spelled out the details Thursday on the wireless service that CEO Brian Roberts announced in September. The newly branded Xfinity Mobile service leverages Verizon Wireless' network and launches mid-year. It will be confined to Comcast customers who already pay for home Internet service, as well as potential new Internet subscribers who reside within Comcast’s footprint. That area covers markets across the nation, but is missing in places such as New York City and Los Angeles.

“It’s really anchored around value-add for the Comcast customer. We’re not taking on the entire wireless industry,” says Sam Schwartz, chief business development officer for Comcast Cable. Comcast has 29 million customer relationships, he says, and is the largest residential Internet service provider in the country.

Even without tackling an entire industry, it makes sense that a cable giant like Comcast would want to plunge into the fluid and fiercely competitive wireless business. The largest traditional cellphone combatants, Verizon and AT&T, are also powerhouses in media, entertainment, tech and broadband, and these companies have wide ambitions that often overlap with Comcast's. They're all jockeying for the mindshare of the consumer, leading to a smorgasbord of compelling but sometimes confusing services that range from blazing fast Internet to fresh streaming mobile content.

Whenever possible, Xfinity Mobile will tap Comcast’s more than 16 million Wi-Fi hotspots. Service will be supplemented by cellular network coverage supplied by Verizon Wireless, which entered a so-called MVNO (mobile virtual network operator) partnership with Comcast that dates back about to 2011. Though Comcast is open about this relationship, the Verizon brand is not part of the direct pitch to consumers, with Comcast only saying it uses the “most reliable 4G LTE network.”

Schwartz says, “every inch of their network will be available to our subscribers as well.” Comcast is promising that its customers will be on equal footing with Verizon customers when accessing that network. (Verizon gains some incremental business.) But Schwartz adds that more than 80% of the data that people consume on their smartphones is over Wi-Fi.

Xfinity Mobile, in fact, will automatically connect your smartphone to Wi-Fi when it is available, though consumers have the option to turn Wi-Fi off in places where cellular might be faster or more reliable.

At launch, phones that work will be an iPhone, or top phones from Samsung or LG. Out of the gate you won't be able to bring your own phone to the service.

By way of comparison, Google’s Project Fi, part of an MVNO partnership Google has with Sprint and T-Mobile, is limited to Google’s own Pixel, Nexus 6P, Nexus 6 and Nexus 5X devices.

Unlimited or pay-by-gig

Xfinity Mobile customers will have two main pricing choices, an unlimited data plan or a pay-by-the gig plan.

The unlimited price will either be $45 or $65 per month per line up to five lines, with the lower monthly price reserved for customers on Comcast’s “best” X1 video packages, typically those that start around $150 per month. Unlimited talk and text is included and there’s no per line access fee.

The pay-by-the-gig monthly option costs $12 per GB of cellular data across all lines on an account, and you only pay for what you use. That makes it a potentially attractive offering for the 70% of customers that Nielsen reports consume less than 5GB per month.

Comcast’s prices are competitive but not always the cheapest in every circumstance. Project Fi costs $10 a gig, though customers pay $20 monthly for voice and texts. Fi customers get refunds for data they do not use. And when it comes to unlimited, Verizon itself has a data plan of $180 for four lines. But in Verizon’s case you’d pay $80 for just one line or $70 per line for two. Under Xfinity’s unlimited plan each line, including the first, will cost $45 (or $65).

Comcast's wireless plan: what it means and is it worth it

Folks with more than one line have the option to mix and match plans. So you might put your kids on the unlimited plan while keeping you and your spouse on the metered gig plans. Comcast says you can switch back and forth without paying a penalty so that if in a given month you’re using more data than you expected under the by-the-gig plan, you can switch to unlimited. You’d have the option to convert back the following month.

Comcast will also have an international voice and data plan but hasn't disclosed pricing yet. And it will throttle or reduce speeds after 20GB of cellular usage.

Will customers want it?

Tech analyst Roger Entner of Recon Analytics says Xfinity Mobile's failure to offer a consumer incentive for switching—Comcast is not paying off rival's early termination fees or assuming remaining device payments—will significantly limit its growth potential.

"Comcast clearly sees Xfinity Mobile as a profit maker not as a market disrupter," he says.

So what is Comcast’s motivation to become a wireless carrier? “On a standalone basis, we will make a small amount of money in the wireless business,” Schwartz says. “But really for us, it’s about the more services you can sell somebody the more they’re going to be comfortable with your relationship.”

Of course, there may be other ambitions for Comcast. One of its traditional competitors in the entertainment space, DirecTV, is now part of AT&T, obviously a major player in wireless. Comcast has also been mentioned at times as a potential suitor for T-Mobile or Sprint.

"I view Xfinity Mobile as Comcast's experimental wireless endeavor with training wheels," Entner says. "They are trying to learn and then decide what to do—everything from building their own network to buying T-Mobile or even Sprint."

Among the hurdles Comcast may face with the Xfinity Mobile launch is overcoming the generally poor reputation cable companies have for service and support.

Comcast Mobile president Greg Butz acknowledges the issue. “That intense focus in our core cable business –we know we need to get better and improve the customer service and customer experience. We know the issue, I think we’re on it.”

Among the ways, the Xfinity offering includes 24-by-7 customer support through text messaging, and through a dedicated call center support team. And the company is adding a personal touch, shipping you a phone and identifying you by name.

Payments are automatically billed through your credit card. And as part of the Xfinity Mobile offering, you can stream up to 200 live TV channels on the go and control your home devices from the road.

Email: ebaig@usatoday.com; Follow USA TODAY Personal Tech Columnist @edbaig on Twitter