As payments executives debate which approach to mobile payments will win out, Bank of America Corp. is showing greater commitment to a system based on Visa Inc.'s specifications.

B of A plans to expand a mobile payments trial it is conducting in New York to San Francisco and Atlanta this quarter, according to Michael Upton, the emerging channels capabilities executive at the Charlotte, N.C., company.

"We have liked what we learned," Upton said of the trial in an interview on Monday. "It does … give us some of the market differentiation in terms of consumer adoption, behavior, preferences [and] perceptions by moving to some of the other markets."

Bank of America also plans to make the system commercially available to customers by the end of the year, Upton said.

The bank began a trial of the system with an unspecified number of employees in New York in September. The expanded pilot program will include employees as well as consumer customers, Upton said.

Bank of America is testing the system using a mobile wallet application that can store one of the bank's credit cards and one debit card.

Visa last month announced that its specifications to offer mobile payments services to bank customers on a commercial basis were available after 18 months of testing, with certain iPhone, BlackBerry and Android handset models certified for use.

"The technology is no longer under pilot restrictions," Dave Wentker, the head of mobile products at the San Francisco payments network, said in an interview Tuesday. "A bank may choose to run a limited test of it, but that's their own decision."

"They don't have to ask us for permission any longer, which is a great place to be for the market to be able to move forward," Wentker said.

That Bank of America plans to offer a commercial application this year is a good signal for mobile payments development, said Beth Robertson, the director of payments research at Javelin Strategy and Research in Pleasanton, Calif.

However, the approach is likely not the end goal for the bank or others, she said, as developers expect smartphones to come pre-embedded with near-field communication technology.

Isis, a mobile payments network being formed by telecommunications companies, is expected to use NFC phones. Separately, Google Inc. has talked about enabling NFC payments in phones that use its Android software.

Visa's approach involves inserting an NFC-equipped microSD card from DeviceFidelity Inc. in to the smartphone's memory slot.

Bank of America is one of four banks with which Visa last year announced plans to do pilot programs. JPMorgan Chase & Co., Wells Fargo & Co. and U.S. Bancorp were also working with Visa.

U.S. Bancorp did not respond to calls or e-mails on Tuesday. JPMorgan Chase declined to comment.

Bank of America may change the current iteration of its mobile wallet app based on trial feedback, Upton said. For example, it may integrate the mobile payments function into existing apps, Upton said; during the test the payment function is accessed through a separate app.

Wells Fargo is using an integrated app for an employee trial it is planning for this year in San Francisco, said Peter Ho, the bank's product manager for card services and consumer lending.

"We don't want our customers to have … three or four different Wells Fargo boxes sitting on their screen," Ho said.