Instructions
Look at the number of USB ports available on the console. Older PS3 models have four open USB ports while newer ones, those created after November 2007, have only two. If the PS3 has two USB ports, then the hardware is completely incompatible with PS2 games. Only those with four USB slots have any possibility of backward capability.
Locate the model number on the back of the PS3. Regardless of model the number always begins with "CECH."
Read the model number. Models "CECHB" and "CECHA" come with hardware that allows them to play PS2 games through the PS3. Models beginning with "CECHE" have software emulation that allow them to play most PS2 games but removal of some PS2 software may cause a few glitches and errors during game play.
Update the firmware on a "CECHE" model to boost its PS2 backward compatibility. This can be done by entering the "System Menu," followed by "System Update" and selecting "Update via Internet." With an Internet connection, the PS3's software will automatically update with the software needed to play PS2 games on the CECHE model of the PS3. The update also smooths out the rough edges seen in PS2 game graphics. No other models can be made compatible through software updates.