MUMBAI: Payment for purchases at department stores is set to get smarter. Mobile wallet and e-commerce platform Paytm will soon launch ‘sound pay’, a feature on its mobile application that allows money transfers and payments using ultrasonic sound waves.“Consumers will soon have the option of clicking the ‘sound pay’ icon in the Paytm app,” Nitin Misra, head of products at Paytm, told ET. “It will transmit ultrasonic sound at a certain frequency and it carries data. The data will include how much to pay and the customers credentials.”According to Misra, once the consumer’s app transmits data, the seller’s app checks whether there is enough money in the Paytm wallet before the transaction is completed. Paytm is currently conducting trials of this service. If successful, the system could be implemented in a couple of months at convenience stores