UltraLink
Acoustic data link — browser to browser, over air
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Send data through sound.

Two devices. No network, no cables, no pairing. Pick a role for each and hold them a few feet apart in a quiet room.

Select a role

How it works

Messages are encoded as binary FSK tones near 18.5–19.5 kHz — a faint high pitch most people can hear, though some cannot. Open the sender on one device, the receiver on another, and transmit.