In this modular industrial controller, all input and output (I/O) functions have been implemented as modules called Tibbits. These modules are installed on a processor board, which carries only the bare essentials: a CPU, an Ethernet port and basic power supply. All other functions are defined by Tibbits. The board and Tibbit modules are installed in the Project Box housing. The front panel of the Box is made of translucent plastic in order to keep Tibbit status LEDs visible, while paper inserts serve to mark ports and wires.