Status detection via current sensors, such as the occupancy detector LB101, has one crucial disadvantage: if the operating voltage is interrupted, so is the power supply. In this case, occupancy detection fails: the signal output will report unoccupied tracks that are, in fact, occupied. Power failures may be caused when the voltage is switched off or short circuits occur. The latter are particularly troublesome since temporary short circuits are a frequent phenomenon in model railway systems. The voltage detector LB050 was designed to prevent faulty feedback. It checks whether digital voltage is applied to the track; if not, the present status will be fed back until voltage is reapplied. The LB050 comes without a case.