There is a section about it on Wikipedia PS/2 page: https://en.wikipedia.org/wiki/PS/2_port#Conversion_between_PS/2_and_USB https://en.wikipedia.org/wiki/PS/2_

There is a section about it on Wikipedia PS/2 page: https://en.wikipedia.org/wiki/PS/2_port#Conversion_between_PS/2_and_USB https://en.wikipedia.org/wiki/PS/2_port#Conversion_between_P... And the page it referenced: https://www.nxp.com/docs/en/reference-manual/DRM014.pdf#page=8 https://www.nxp.com/docs/en/reference-manual/DRM014.pdf#page... In Page.11, it show the algorithm to distinguish PS/2 and USB, based on USB D+ and PS/2 clock signal.