@alvin I could use a wifi-to-ethernet device (I have and old one at home, so no cost added).
I would like bluetooth because the system is mounted in a self-made cabinet for two players, and I liked the idea of adding 2 extra players

I have installed recalbox on an old computer, which lacks bluetooth and wifi. I have found a wifi usb compatibiliti list, but I couldn't find a bluetooth one. Other than that, the computer has a "mini-pci" slot; should I go the USB way? or I should better search for an old pci adapter?

Thanks for your advice