The Chirp app for iPhones and iPads gives your phone a bird song approach to sharing data with other phones. Your device will sing a song through its speaker and the receive song will hear it and get what you’re trying to share.
Cynics and skeptics might stop at the point where they say that it’s not very secure or that it’s basically just a modem all over again. But from the app’s comments on iTunes, the real criticism seems to be that data isn’t actually transferred with the song. Instead, the sending app uploads it to their server and the song carries over an identifier for the receiving app to download it from the Chirp server. A data connection is required and while it is a quirky and neat app, it seems less neat when you see some of the limits that the video is less straight-forward about.
“Inspired by birdsong – Chirp is a new app that uses sound to transfer data.” It is transferring data but a very small amount is actually transferred by sound, it mostly just coordinates the transfer through the usual means.