Credit Cards (image) University of Washington Share Print E-Mail Caption Researchers demonstrate how one payment card can transfer funds to another card by leveraging the existing wireless signals around them. Ambient RF signals are both the power source and the communication medium. Credit University of Washington Usage Restrictions Photo credit required. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.