NCE AIU01 - Auxiliary Input Unit -- For Block Detection - NCE 5240200The Auxiliary Input Unit (AIU) provides a means of connecting external devices such as switch contacts, Block Detectors (BD20), or other sensors to the NCE Cab Bus or Command Station. These external devices can be anything that supplies an electrical connection between the input pins (1 14) and the pins marked "GND" Connects to the NCE cab bus using RJ12 6 wire jack.