Verizon Wireless plans to open its network to devices other than the ones hand-picked by the company, a move that could expand the features available on mobile phones and give the second-largest U.S. wireless carrier a response to a phone software project led by Google Inc.

The decision, announced yesterday, means that customers would be able to buy devices of their own choosing and run them on Verizon's network. Traditionally, wireless providers like Verizon let customers pick only carrier-approved devices, with carrier-approved software features.

The model has some benefits for consumers because many of the available phones are subsidized by the wireless provider. That means devices that would otherwise cost hundreds of dollars are available for less than $100 or even for free.

But because this "walled garden" approach dictates which services customers can use — so as to maximize profits for the carriers — the traditional model has not created a broad, open environment commonly thought to best encourage outside software developers. It is as if some Web sites ran only on certain brands of PCs.

Verizon's new plan, which is expected to be running by the second half of 2008, will hardly be taking a sledgehammer to the walled garden. The traditional model, in which Verizon selects phones to sell, will still exist. And the company will let customers operate other phones on its network only if the devices have passed tests, which their manufacturers will pay for, in a Verizon lab.

Even so, Verizon's announcement indicated it was willing to try out the idea that customers want more flexibility in what they can do with their phones — even though it could force the carrier to make do with being a basic provider of wireless access rather than a value-added content provider as well.

Yesterday's news gave Verizon Wireless — a joint venture of New York-based Verizon Communications Inc. and Britain's Vodafone Group PLC — the second landscape-shifting announcement in the wireless industry this month.

In hopes of making Web surfing and other advertising-supported features more prevalent on cell phones, Google said Nov. 5 it was developing a free software package for wireless devices to operate on.

Key phone makers, including Motorola Inc., Samsung Electronics Co. and LG Electronics Inc., have agreed to use it in some devices. And some wireless carriers, including Sprint Nextel Corp. and Deutsche Telekom AG's T-Mobile, have said they would support devices with the software on their networks.

Verizon Wireless is not in the mix, at least for now. (Nor is the largest U.S. wireless provider, AT&T Inc., the sole domestic carrier of Apple Inc.'s innovative iPhone.) However, Verizon Wireless spokeswoman Nancy Stark said a phone with the Google software could make it onto Verizon's network through the new plan to let customers buy their own devices separately.

The flexible approach was praised by the Federal Communications Commission chairman, Kevin Martin, who has pushed carriers to allow open-access freedoms as a condition of an upcoming auction of the airwaves. And telecommunications analyst Dave Burstein, editor of the DSL Prime newsletter, predicted that the "wonderful" new approach would lead to phones with such innovative specialties as extremely cheap international calling or exceptionally long battery life.