Using sound for transferring data is nothing new. In the 1940s, when IBM tried to solve the problem of how to use regular telephone lines to connect two computers, it figured out a way to convert data into sound, send the sound over the phone and then convert it back into data. (Yes, I'm talking about the modem.)
The benefit of using sound for data transmission was that equipment to handle the process was widely available.
In the wireless era, sound is still a great option for data transmission and other uses, and for the same reason.
Lately there's been a surge of innovations that harness sound waves to transmit data and do other creative things. Here's what's going on.
Some of the new sound-based technologies use ultrasonic frequencies — sound that's too high-pitched for people to hear.
Google this month shipped a new guest mode for its Chromecast digital media player HDMI dongle. The mode lets Android phone users control a Chromecast without connecting the normal way, via Wi-Fi. Instead, the guest mode uses ultrasonic technology to communicate through a TV's speakers. The ultrasonic tech "pairs" the TV and the Android phone using a four-digit PIN code sent via sound. After that, the control takes place over the Internet (with the TV continuing to use your home's Wi-Fi and the phone using its own mobile broadband connection).
The beauty of this technology is universality. Every TV has the necessary "networking equipment" — speakers. Every smartphone has the right stuff, too — a microphone. That's all you need to transmit sound from one place to another.
A U.K. company called Chirp lets you send data via sound. The basic use case is to send a picture to someone nearby. (Both people need to have the Chirp app running.) Just take or select a picture, then click the yellow Chirp button in the app. The app makes a noise. If the other person accepts the picture, it appears on his phone.
What's really happening here is not that the picture is transmitted through the sound. The phones are simply pairing, and the picture is being uploaded, then downloaded, through each phone's respective Internet connections.
What's cool about it is that if 10 people have the app, all 10 can get the picture in the same way by all hearing the same sound. It's great for presentations, or even TV commercials, theoretically.
An app called Clinkle (for iOS and Android) lets you transfer money from one installation of the app to another. Each person's app needs to be preconfigured with bank or credit card details.
Clinkle has an interesting patent for something it calls Areolink, which is an ultrasonic method for transmitting money via sound from one phone to another.
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