An Israeli researcher with a history of technology research and findings, has located a technique of using a computer's USB port as a mini RF transmitter.

Mordechai Guri, used air-gapped PC’s to find that by modulating the data fed at high speed to plugged-in devices, a string of “0” bits could be transmitted from the USB port detectable between 240MHz - 480MHz.

Guri wrote a sequences of '0' and '1', creating a carrier wave from the rapid voltage changes on the interface's data pins, then binary frequency shift keying (B-FSK) to encode useful information into the wave.

Guri estimates that transmissions of 80 bytes per second can be achieved over the air using this technique.

Full Story - http://www.theregister.co.uk/2016/08/31/usbee_shows_once_again_that_airgapping_doesnt_protect_squat/