The Omron C200H-LK201-V1 is a Host Link Unit (RS-232C communication module) designed for the SYSMAC C200H series PLC. It establishes a reliable serial communication interface between the PLC and host devices (e.g., PCs, programmable terminals, HMIs). Supporting the Host Link protocol, it enables program upload/download, real-time status monitoring, data read/write, and remote control.