LISNR® is the creator of a proprietary near-ultrasonic protocol that sends data-over-audio. Originally coined Smart Tones™ in 2012, our audio technology has evolved into the KAB® (Kilo Audio Bit). LISNR®’s protocol sends data-over-audio across bandwidths (14.5 kHz-19.2 kHz) that are audible or inaudible, depending on use case and distribution method, to ensure optimal performance.

Each tone has 3 parts:




The Preamble

The tone preamble announces the presence of a tone to begin SDK demodulation.

The Header

The header contains metadata about the payload and security logic.

The Payload

The payload is the actual data-containing portion of the tone.

Performance Optimization

We’ve created multiple tone types and profiles, optimized for varying payload and environment characteristics of the use case. All tone profiles and types are compatible with a single SDK.

Standard Profile

Inaudible: Has a frequency range of 18.75-19.2 kHz. This profile has been optimized to solve the problem of reverberation and increase reliability.

Compression Profile

Audible: Has a frequency range of 14.55-15 kHz. Similar to our standard profile, but optimized for implementations that have frequency range restrictions such as FM radio, video, and audio streaming.

Precision KAB® Profile

Inaudible: Has a frequency range of 18.0-19.2 kHz. This profile has been optimized to work best in live environments at close distances.

ID Tones

Displays as an image, web link, video, etc. that is stored within a third party content management system.

Text Tones

Displays as text only (ASCII) and can be locally generated in offline environments.

Data Tones

Displays as binary data and can be locally generated in offline environments.



LISNR® transmits data using a similar methodology used by other protocols (preamble, header, payload) and can employ industry standard security/encryption methods. Customers can locally generate tones on devices and send encrypted data creating secure communication between devices. LISNR® customers also have the ability to apply additional encryption to their payload to create a more secure data exchange.


Our technology enables a seamless and consistent connectivity experience regardless of the operating system, device, or environment. Five years of development have gone into optimizing proprietary tone profile and data types.

Low Power

As an always-on communication protocol, LISNR® outperforms the rest, especially when it comes to power consumption when compared to RF-based connectivity or audio fingerprinting options. Our technology has proven itself to be the most battery and CPU efficient across the entire software spectrum, from the application level to the embedded system level, with significant advantages to power optimization at the chipset level.


As our payload continues to increase, our current innovation the KAB® (Kilo Audio Bit) has throughput of 1,000/bits-per-second.

Tone Profiles

To maintain payload reliability, we created optimized tone profiles for use such as range (short/long), digital media compression (audible version), and data payload. All tone profile types are compatible to a single SDK.

Data Payload Types

Optimized tone data types for use such as text (ASCII), ID, and data (binary) types maintain reliability. All tone data types are compatible to a single SDK.

Local Tone Generation

This enables local data encoding and decoding for device-to-device communication without server connectivity.


With best-in-class performance metrics in reliability, data payload, security, and operating efficiency, LISNR®’s proprietary technology is on pace to become the industry standard in data-over-sound technology.

Intellectual Property

In addition to proprietary, best-in-class performance, LISNR® has the earliest global IP filing date for comparable data-over-audio solutions.

LISNR Software

LISNR®’s technology is built within a C-library base conveniently allowing adaptability across the connected world ecosystem. This library allows interoperability across all software applications from device operating systems to chip-level embedded systems.

In order to decode the data present in the waveform, the audio is run through a software program. Our SDKs only recognize LISNR® audio that falls within the specified frequency range, filtering out the rest.

LISNR® Portal

This is the central developer dashboard to access, manage, and demo LISNR® technology use.


The LISNR® software development kit encapsulates the functions needed for devices to utilize our technologies on various platforms, allowing for tone modulation and demodulation. We currently support the following platforms:

  • Android*
  • iOS*
  • Linux*
  • Windows*
  • Python*
  • JavaScript
  • Raspberry Pi*
  • Amazon Alexa
  • macOS*
  • Customized Wrapper

*Full modulation & demodulation


Our application program interface allows customers to seamlessly integrate LISNR® services within their systems by making simple HTTP requests.


This allows clients to view specific metrics related to how their customers are interacting with their LISNR® integration.

LISNR® Diagnostic App

Available to LISNR® Portal users, this is used for testing tones created via the LISNR® Portal and local device-to-device transmission over sound.

Resources &

Our library offers support documentation to create and facilitate deployment.


Broadcasting and receiving data via is sound is powered by integrating our software. We provide a simple communication method that can be layered into any existing software, device, service, or media. As you design the ideal experience, the end user can be the broadcaster, the receiver, or both. LISNR® can carry the current data you are using offline from one device to the next. To meet LISNR security standards, additional tokenization should be applied to LISNR® ’s header and encryption to the payload.

Let's Start Building

Learn how to start sending data over audio, or just drop us a line. We'd love to hear from you.