SAN FRANCISCO (AP) — Financial services startup Square is trying to turn the swipe of a credit card into an act of generosity.

To pull it off, Square is unveiling a red credit card reader that will serve as a charitable alternative to the millions of white readers the San Francisco company has distributed since its inception five years ago. The Square readers plug into the headphone jack of smartphones and tablet computers so the devices can become electronic sales terminals, empowering more merchants to accept credit cards.