Google has introduced a new payment app in India called Tez (the Hindi word for “fast”). Tez features a technology called audio QR that allows users to transfer money using sounds to pair two devices. Called the “cash mode option,” phones negotiate a connection using audio to identify the payer and payee. (The sounds should be inaudible to human ears though because they’re sent using ultrasonic frequencies, according to the Financial Times.) The feature is therefore similar to cash transactions which don’t require the exchange of personal details like bank accounts and phone numbers. Cash Mode works with any phone with a mic and speaker and Tez app installed, and doesn’t require an NFC chip. Google’s Audio QR technology is similar to Chirp, which also sends data encoded in ultrasonic audio.