Quiet Modem Project

Quiet Modem Project is an easy way to provide low-throughput communication for websites and apps without requiring access to Internet or pairing between two devices. It is a set of cross-platform libraries that allow you to encode data as sound and transmit it with a speaker. A device or application with the Quiet Modem can then detect this sound and receive the encoded data. This sound can be audible or nearly ultrasonic. Forward Error Correction applied to the message helps preserve the data against errors in transmission, while Checksums discard messages received incorrectly.

Live Demo

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All of the Quiet Modem's libraries, and its dependencies, are licensed under a mix of BSD and MIT, allowing a versatile range of use cases. Quiet's source is freely available and can be audited, which ensures that your user's microphone data is safe. Quiet Modem is offered in C, Javascript, Android and iOS. It provides bindings to soundcards on each platform so that you can simply encode data on one side and decode on the other.

The Quiet Modem is configured with a JSON-based profile system that allows you to change a wide range of behaviors at runtime. Quiet is built on top of a highly capable DSP/SDR library which provides it with good robustness, even at distances up to 1 meter.