|A simple gender adapter that you plug into the connector on the end of a cord - e.g. PS/2 female to USB male, or USB female to PS/2 male - only works with "combo" keyboards or mice that are designed to be and wired up to be used with both types of connection. "Combo" mice and keyboards come with such an adapter when new. |
Ones for mice - often colored green - often won't work with a "combo" keyboard, and ones for keyboards - often colored purple - often won't work with "combo" mice, because not all the connections in the adapter for use with both types are there.
Some generic PS/2 female to USB male, or USB female to PS/2 male, simple adapters (that are not colored green or purple) can be used with either a "combo" keyboard or "combo" mouse.
There are USB male to 2 - PS/2 female adapters that have extra circuitry between the two ends - that's often in an obvious bulge or enclosure in the cable between the two ends - that allow you to connect a regular PS/2 mouse, or a regular PS/2 keyboard, or both, to a USB port, but older bioses may not recognize that a PS/2 keyboard has been connected and you may or may not be able to get into the bios Setup, even when USB keyboard or USB legacy devices or similar is enabled in the bios Setup.
If you use a USB keyboard, the setting USB keyboard or USB legacy devices or similar must be enabled in the bios Setup in order for you to be able to get into the bios Setup with it. Usually that's enabled by default in newer bios, NOT enabled by default in older bioses.
You can always get into the bios Setup with a PS/2 keyboard, or with a "combo" keyboard with the proper (often purple) USB female to PS/2 male simple adapter plugged into the USB male connector on the end of the cord.