PAL PSone have a region lock. You will need to use a ONEchip programmed PIC to circumvent the region lock, or you will only be able to play PAL backups.
As the others have stated, same RGB cable for the first three generations of PlayStation. A PSone can also decode NTSC colour via composite though, if you're that way inclined.
Edit: Actually the video chip outputs PAL60 instead of NTSC so my above statement was slightly incorrect. PAL models of PlayStation starting SCPH-7xxx and later all do this. Previously they did true NTSC.
Comment