Instructions
Disconnect all of the cables and wires from the PlayStation 3 system.
Lift the PlayStation 3 and find the bar code sticker on the rear of the system. Beneath the bar code is a series of characters labeled "Serial." This is the unit's 11-digit serial number, which is followed by a dash and a model number that begins with the letters "CECH."
Use the model number to determine your system's backwards compatibility. Models CECHE01, CECHA01 and CECHB01 are backwards compatible with PlayStation 2 and PlayStation 1 games. All other PlayStation 3 models are not backwards compatible.