It’s a Monday afternoon and Bank of America credit card executive David G. Turner is doing what he loves: showing off new gadgets.

There’s a cell phone that can be used as a credit card and a kiosk that generates new cards on the spot. And best of all, Turner points out as he stands in Bank of America’s Wilmington, Del., card development lab, there’s a vending machine that doesn’t need cash or change. He flashes a card in front of a specially equipped reader and a cold bottle of Dasani water drops into his hand.

“I just bought you a bottle of water with a credit card,” he says.

Although Turner is having fun, he’s also a businessman looking for ways to help Bank of America crack the stubborn slowdown that dogs the credit card industry. Analysts describe the U.S. credit card market as saturated, with nearly a billion credit cards in circulation.

The credit card industry is eyeing the millions of small payments that happen daily at fast-food restaurants, vending machines and convenience stores. The banks hope to capture these transactions with new gadgets such as radio-frequency credit cards and payment-making cell phones.

Card executives bet they can reignite profit growth by using radio-frequency credit cards and other devices to capture more of the $4.4 trillion in annual U.S. spending done through cash and checks.

Getting the country to embrace new technology isn’t easy, however. Consumer advocates raise concerns about security of radio-frequency payments. And, like other longstanding habits, consumers appear reluctant to alter the way they’ve been paying for decades.

But change is occurring. Cash and checks now account for 45 percent of consumers’ monthly payments — down from 57 percent in 2001 and 49 percent in 2003, according to research from the American Bankers Association and Dove Consulting.

For now, analysts say, the most obvious opportunity for Bank of America, Chase and other credit card-issuing banks is to get consumers to move cash and check purchases onto cards.

Every time a consumer charges a purchase rather than pays in cash or by check, retailers pay the credit card banks a fee. A fraction of every card purchase, the fees add up to hundreds of millions of dollars. On top of that, banks charge interest on the unpaid portion of cardholders’ monthly balances.