How to make your own ps/2 to usb convertor for old keyboards
The converters like these:



are just for the connections.

It will not make a USB-only keyboard work in PS/2.

It will not make a PS/2-only keyboard work on USB.

The keyboard that came with such an adapter was capable of both USB and PS/2 connections. It detects if it is plugged into a USB port or a PS/2 port and then adapts to that connection type.