Extend a compatible switch uplink or inter-switch connection across single-mode fiber with 1,310 nm LX optics. The TP-Link Omada SM311LS is an SFP-format optical transceiver rated for up to 1.25 Gb/s and a maximum link distance of 20 km. Its duplex LC interface connects to 9/125 µm single-mode fiber, providing separate transmit and receive paths through a standard two-fiber patch lead. Install the module in a compatible SFP port to carry a 1 Gigabit Ethernet link beyond copper Ethernet distance limits. IEEE 802.3z support makes it suited to fiber runs between wiring closets, floors, buildings, or remote network cabinets where single-mode cable is already installed. The transceiver uses CSMA/CD protocol operation and supports operation from 0 to 70°C at 10 to 90% humidity. Within compatible SFP optical options, this model is defined by its single-mode LX optical interface, 1,310 nm wavelength, duplex LC connection, and 20 km maximum reach. Those attributes matter when matching the transceiver to installed fiber type and the optic at the far end of the link. Storage conditions are rated from -40 to 80°C.