The PSIO is a special device that plugs into the parallel port on a PS1. It lets you boot games from an SD card instead of using a CD. This is the official PSIO module from ps-io.com. I don’t use clone hardware.
A switch board is soldered into the mainboard so that CDs and SD cards can be used.
More info on https://ps-io.com/
There will be a delay of a few weeks because I don’t currently have any PSIO modules. I have to import it from Australia where it’s sold from
Send me your PS1 and I’ll install the switchboard for you and ship it back to you with the PSIO and an SD card, ready to play!
NOTE: Only for PS1 SCPH-75xx and earlier. Later consoles don’t have the parallel port needed for PSIO. Please check that the parallel slot is present on your playstation before sending to Minifree. NONE of the slim PS1s are compatible