HIDman is an open source device to allow the use of modern USB keyboards and mice on legacy PCs.

Peripherals that support legacy PCs are becoming hard to find, especially for the very first PCs. This project aims to provide a simple cheap solution that will cover everything from the original IBM 5150 PC all the way up to modern computers that have PS/2 ports.

You will also need to order the Front enclosure plate : https://www.pcbway.com/project/shareproject/Front_enclosure_plate_for_HIDman_0aec2ae9.html

And the Rear enclosure plate : https://www.pcbway.com/project/shareproject/Rear_Enclosure_for_HIDman_c0ff0b8a.html

Grab the rest of the case from here : https://lincolnbinns.com/e-case-a-black-40mm.html

Don’t forget 8x screws : https://lincolnbinns.com/e-case-screws.html (I suggest the thread former ones)

You can find ps/2 cables, serial cables, etc from ebay or aliexpress.