Most USB ports have a chip between it and the host controller for electrostatic discharge (ESD) protection. The nicer ones can also sense shorts and overcurrent

Most USB ports have a chip between it and the host controller for electrostatic discharge (ESD) protection. The nicer ones can also sense shorts and overcurrent on the lines and signal the processor that something is up. Example: https://www.maximintegrated.com/en/products/power/protection-control/protection-ics/MAX4987AE.html https://www.maximintegrated.com/en/products/power/protection...