This user guide provides detailed instructions for installing and configuring the Modicon MCSESR Redundancy Switch. It includes safety information, device description, installation procedures, and technical specifications. The guide covers various aspects such as connecting power supplies, signal contacts, Ethernet ports, and management interfaces. It also provides information on device status indicators, first login procedures, and maintenance requirements. The document is intended for qualified personnel responsible for installing and maintaining industrial automation equipment. AI-assisted summary (Full document authored and validated by Schneider Electric experts).