From a Tweet by Lu to his video on Youtube presenting the HIDMAN by Rasteri which let you use USB keyboard/mouse on a PC XT, AT, serial and PS/2 port, like the Amstrad PC (PC1512, PC1640, PC2xxx, PC3xxx, PC4xxx) and more as stated on the HIDMAN's github page by Rasteri where you will also find a shop to < a href="https://retrohackshack.com/product/hidman-usb-keyboard-converter/">buy this accessory on Retroshack.