The Omron CS1W-SCU21-V1 is a serial communications module designed as a CPU Bus Unit for the Omron CS series, providing reliable and flexible data exchange between PLCs and external devices. Equipped with two RS-232C serial ports, it enables stable communication and seamless integration with a variety of industrial components. Fully compatible with Omron CS1-H CPU units, the CS1W-SCU21-V1 supports multiple communication protocols, including Host Link, NT Link, Serial Gateway, and loopback test modes, ensuring adaptability across different automation setups. It can be installed on either a CPU rack or an expansion rack, with support for up to 16 units per rack for scalable system configuration. The CS1W-SCU21-V1 could be deployed in industrial automation systems throughout North America, Europe, Asia, and other worldwide markets, offering dependable serial connectivity and versatile communication control for advanced PLC networks.