The GE Fanuc Series One Junior Programmable Controller is designed for control applications requiring 4 to 60 relays. A Series One Junior, being compact, requires only 53 square inches of mounting area, which is about the same space as four 4-pole relays. The unit has a fixed number of I/O points in its compact design.

Each Series One Junior PC provides 24 I/O, which includes 15 inputs and 9 outputs. The input terminals are located at the top of the unit and the output terminals and power source connections are located at the bottom of the unit.