The RCX (Robotic Command eXplorer) is the brains of your robot. It contains a microprocessor that reads sensors, controls the motors, and runs your programs. The RCX has three sensor input ports (1, 2, and 3) and three motor output ports (A, B, and C).

The On-Off button turns the RCX on and off. The RCX will shut itself off automatically after 15 minutes unless that capability is disabled. The Run button on the RCX runs the program. You can store up to 5 different programs in the RCX at a time. The Prgm (Program) button lets you select which program to run. The View button lets you see what the sensors are reading and which way the motors are running. Press the View button multiple times to select which port you want to view. Programs that you write are downloaded to the RCX brick with the InfraRed Tower.