The FRM220-OPS51M is a Multi-mode Fiber Optical Protection Switch designed to provide fiber path redundancy on a channel-by-channel basis, ensuring reliable data transmission. It is optimized for use with 50/125µm Multi-mode fiber at an 850nm wavelength, offering robust protection for fiber optic links. The unit features quick traffic switching, taking less than 50ms in case of a fiber cut, and operates with a monitoring system that tracks the status of the active fiber path via SNMP management when installed in an FRM220 rack. This protection switch can be configured to enable or disable ports, reset ports, and set receive threshold levels for automatic path switching. It includes a latch feature that maintains the current state during a power loss, and supports both non-revertive and manual switching modes. With LC connectors and physically separated working and protected fiber lines, the FRM220-OPS51M ensures high channel isolation and stable, reliable performance for critical fiber optic applications.