Air gaps can also be bridged by using radio or sound waves. There could be a bunch on non-networked computers in a secure lab all talking to each other. This assumes trojaned hardware and&#x2F;or operating system software in the systems that can send and receive data and commands.<p>Finally, technology such as Morse Code is still useful in these scenarios. Dits and dahs. Zeros and ones. That&#x27;s all you need to be able to send and recv data.<p><a href="http:&#x2F;&#x2F;www.jocm.us&#x2F;index.php?m=content&amp;c=index&amp;a=show&amp;catid=124&amp;id=600" rel="nofollow">http:&#x2F;&#x2F;www.jocm.us&#x2F;index.php?m=content&amp;c=index&amp;a=show&amp;catid=...</a><p><a href="http:&#x2F;&#x2F;www.wired.com&#x2F;wp-content&#x2F;uploads&#x2F;2014&#x2F;11&#x2F;air-hopper-malware-final-e-141029143252-conversion-gate01.pdf" rel="nofollow">http:&#x2F;&#x2F;www.wired.com&#x2F;wp-content&#x2F;uploads&#x2F;2014&#x2F;11&#x2F;air-hopper-m...</a>