Siemens 505-6851-B is a Remote Base Controller (RBC) module for the TI505 family of SIMATIC PLCs, delivering the RS-485 interface that ties a central TI505 processor to remote I/O racks. As part of the 505 RBC family (A/B variants), it handles the communications channel that coordinates distributed input/output devices in legacy Siemens TI505 installations. Designed for automation configurations that require expanding field I/O via RBCs, the 505-6851-B enables centralized programming and monitoring of distributed I/O through the TI505 control network.
