Ansaldo N451810-6602 MicroLok II Module

The N451910-6602 IN4OUT4 Non-Isolated I/O PCB is a four-input, four-output module designed for the MicroLok II interlocking system, intended to plug into a MicroLok II cardfile and provide non-isolated digital I/O signals for track-circuit interfacing and signaling devices. In 24-volt variant form, the 6602 suffix identifies 24V operation; a 6601 variant exists for 12V, and the IN4OUT4 family consistently provides four inputs and four outputs that connect to signaling circuits used in railway applications. This PCB is part of the MicroLok II ecosystem from Ansaldo STS (formerly United Signals & Signals), commonly used to interface local control logic with track-side equipment, with the CPU and multiple I/O boards housed in the cardfile. Its non-isolated design shares a common electrical reference with the MicroLok II logic, a standard characteristic of this I/O family within the system. Typical installations pair this module with the CPU and other I/O or track-circuit PCBs to support signaling tasks such as reading track conditions and driving local actuators.