Cable unit for Fanuc I/O communication unit. One way for robots to communicate with their industrial environment is through I/O communication. I/O is a serial interface with a purpose to transfer I/O signals (bitdata) between devices, cell controller, the I/O Unit-MODEL A, the PowerMate, and so on at high-speed. Fanuc Model A I/O components allow for I/O exchange with industrial devices such as sensors, plc's, process controller, welds, and much more.