The company that decided the most underused network on earth was the one already in your pocket - your speaker, your microphone, and the air between them.
The LISNR wordmark, photographed mid-broadcast. Somewhere in this room a tone is playing that you cannot hear and your phone can.
Walk up to a counter. Hold up your phone. No tap, no scan, no Bluetooth handshake. A speaker plays a chirp pitched too high for human ears, your microphone catches it, and a transaction clears. That is a normal afternoon for LISNR.
LISNR is a technology company in Cincinnati, Ohio, with a staff that fits comfortably in one large room - roughly 31 people - and an ambition that does not. Its product, the Radius ultrasonic SDK, treats sound the way most companies treat radio waves: as a carrier. Inaudible frequencies the company calls Smart Tones leave any ordinary speaker, travel across a room, and deliver a packet of data to any device listening. Proximity detection, identity verification, contactless payment - all of it riding on a medium that has been sitting unused in every device for a century.
The pitch is almost annoyingly simple. The hard part, as it turns out, was everything else.
Contactless commerce has a hardware problem. NFC - the technology behind tap-to-pay - is fast and secure, but it needs a chip in the phone and a reader in the terminal. QR codes need a clean line of sight and a steady camera. Bluetooth beacons need pairing, batteries, and patience. Each solution works beautifully right up until the infrastructure isn't there, the connection drops, or the device is too old, too cheap, or too foreign to play along.
That gap is large. Whole markets run on phones without NFC chips. Stadiums and transit hubs swallow cellular signal. Cars, vending machines, and ticket gates all want to recognize a customer without asking them to install one more thing. The world is full of speakers and microphones - billions of them, already deployed, already paid for - and almost none of them were being used to move data.
LISNR's founders looked at that and saw a network hiding in plain sight.
In March 2012, five people from Cincinnati climbed aboard the Startup Bus - a competition where you have 72 hours and a moving vehicle to turn an idea into a company - bound for South by Southwest in Austin. By the time the bus reached Texas, LISNR existed. Rodney Williams, a Procter & Gamble brand manager who had walked away from a six-figure salary, was the loudest voice in the room. Chris Ostoich, Josh Glick, and Chris and Nikki Ridenour were the rest of it.
There is a detail here that most origin stories quietly skip. LISNR was founded in 2012, but it did not actually invent its core technology until 2014. For two years, the company was a conviction in search of an engineer. Williams credits an early hire, developer William Knauer, with finally making the sound carry data the way the pitch promised.
The bet was that sound could do a job radio waves had monopolized. It was the kind of bet that sounds obvious in hindsight and reckless at the time. CincyTech put in $250,000 in 2013 - before the technology fully worked - which tells you something about either the idea or the salesmanship. Probably both.
Radius is the heart of it. Developers drop the SDK into an app, and the app gains a new sense: it can speak and listen in ultrasonic. The frequencies sit above the range of human hearing, so a Smart Tone can play through a stadium PA, a car stereo, a checkout terminal, or a phone, and no customer ever notices. Devices more than ten feet apart can exchange data. No internet, no NFC, no Bluetooth pairing, no QR code in the camera frame.
Authenticate and clear a payment using only a speaker and a microphone - useful exactly where NFC infrastructure is missing.
Prove a person or device is physically present at a gate, counter, or fulfillment point before a transaction completes.
Trigger location-based offers, rewards, and gamified loyalty the moment a customer is in earshot of a tone.
The company holds 131 patents - about six times what its peers carry - which is its way of saying the simple idea is fenced with a great deal of hard engineering.
A clever idea is cheap. A clever idea that Visa and Mastercard both fund is something else. In 2019 Visa made a strategic investment, openly framing LISNR as a challenger to the technology behind Apple Pay. By the 2020 Series C, Mastercard had joined too - which means two of the fiercest rivals in payments decided the same small Ohio company was worth a seat. NTT Docomo Ventures came along for the international angle.
The client list reads like a cross-section of places people gather and spend: AT&T, Ticketmaster, Live Nation, Heineken, Jaguar Land Rover, Target, Synchrony Financial, IDEMIA, SAP. Jaguar Land Rover's general manager called LISNR "one of the most compelling technologies we've seen." In 2024 the company partnered with Refill Technologies to put ultrasonic authentication into ticketing and mobile ordering, the unglamorous middle of commerce where proximity verification quietly matters.
Approximate disclosed amounts, USD. Series C amount was strategic / undisclosed.
Investors include Visa, Mastercard, Intel Capital, Mercury Fund, Jump Capital, Synchrony Financial, R/GA and NTT Docomo Ventures.
LISNR describes what it is building as proximity-based engagement: helping merchants recognize, talk to, and transact with a customer by stitching the digital and physical worlds together. Strip away the phrasing and the goal is a universal data-over-audio layer - a quiet protocol running on the speakers and microphones already in the world, requiring no one to buy new hardware.
That last clause is the whole argument. Every other contactless technology asks the world to upgrade. LISNR asks it to listen.
Walk back to that counter. Hold up your phone. The chirp plays, too high to hear, and the transaction clears - in a market with no NFC terminals, in a stadium with no signal, on a phone too old to tap. The thing that made the moment work was already in the room. LISNR just taught it to talk.
Whether sound becomes the standard or stays a clever specialist is still an open question, and a skeptic is right to keep it open. But the company has spent more than a decade and 131 patents arguing that the cheapest network is the one nobody noticed. Two rival payment giants, several stadiums, and a luxury carmaker have decided that argument is worth funding. The rest of us simply can't hear it happening - which is, more or less, the point.