Keep legacy optical infrastructure in service with a compatible OC-3 LR SFP built for long-reach single-mode deployments. This AddOn Networks transceiver is designed for OC-3 applications using 1310 nm optics and LC connectivity, giving network teams a practical replacement path for systems that still depend on established SONET/SDH-era transport interfaces. The 40 km reach makes it appropriate for campus interconnects, metro edge links, and carrier access segments where distance and optical budget matter. By matching the expected form factor and wavelength profile, it helps reduce the risk and delay associated with sourcing original modules that may be harder to procure. Choose this module when uptime depends on maintaining compatibility with installed optical hardware. It offers a focused, deployment-ready option for extending or restoring service without redesigning the transport layer.