PS1:Region Information

Playstation Region information
All regular retail models of the PSX are region locked and will only play software from their original region. There are 3 different software regions, but for marketing reasons there are 4 different regional console variations.

The intended operating region is indicated by the last digit of the model number, as follows:

SCPH-xxx0: Domestic Japanese units
These have a 100V AC 50/60Hz PSU, are region coded to NTSC-J, and have NTSC video clocks and a Japanese boot ROM. The Japanese boot ROM has a second region check that checks the system area of the disc for the NTSC-J license data and will reject the disc if there is a mismatch (even a single byte - it has to be exact 1:1). The earlier production SCPH-1000s are an exception to this - they still have the license area check and will suppress the display of the black boot screen if it fails, but will boot the disc anyway. This was probably simply an error, since it was changed in the later SCPH-1000s and all subsequent models to stop the boot process entirely. The NTSC-J CD controller chip also lacks the backdoor commands that the NTSC-U/C and PAL versions have, so the CD controller can't be unlocked and use of an original NTSC-J disc is needed for disc swapping, even when using an exploit.

SCPH-xxx1: USA/Canada units
These have a 120V AC 60Hz PSU, are region coded to NTSC-U/C, have NTSC video clocks and an English boot ROM.

SCPH-xxx2: Europe/Oceania units
These have a 220V AC 50Hz PSU, are region coded to PAL, and have PAL video clocks and an English boot ROM. Earlier units (before the SCPH-7002) have a tiled grey boot menu rather than the blue+rainbow menu present on NTSC and later PAL units. The SCPH-102 PAL PSone also has a boot ROM region check similar to the one seen in the Japanese units (although obviously checking for the PAL license data).

They have a sub-region, only affecting the bundled accessories and box/manual languages:
 * A = Oceania = composite cable
 * B = UK/Ireland = RF modulator
 * C = Europe = composite cable and RCA to SCART adapter

SCPH-xxx3: Asia outside Japan units.
These have a wide range 110V-240V 50/60Hz PSU, are region coded to NTSC-J, have NTSC video clocks and an English boot ROM. Since they use the English boot ROM (identical to the one in the NTSC-U/C consoles) they don't have the secondary region check that the domestic Japanese units do, but since they are using a NTSC-J CD controller they still lack the backdoor commands.

Exclusive to the SCPH-5903 is its famous Video CD support, implemented with a dedicated motherboard (PU-16) with appropriate dedicated modifications, but most of its meat is on a dedicated card (MP-45) which implements a rather crude and mostly independent VCD hardware player. The MP-45 is automatically switched in after a VCD is detected, which can only happen in the official BIOS after PS1 disc detection fails.