TP-Link SM321A-2 Gigabit Single-Mode WDM SFP Module
Overview
The SM321A-2 is a wavelength-division multiplexed (WDM) bi-directional SFP transceiver designed to extend Gigabit Ethernet links over single-mode fiber at distances up to 2 km on a single fiber strand. Transmits at 1550 nm and receives at 1310 nm, allowing one fiber to carry bidirectional traffic. Deployed in network infrastructure where fiber runs already exist or where cost-effective long-distance Ethernet extension across campus, warehouse, or facility grounds is required—particularly in security systems needing isolated, noise-immune connectivity beyond copper limits.
Compatibility
The SM321A-2 installs into any Gigabit SFP slot supporting hot-swappable SFP modules, including TP-Link Omada managed switches and third-party switches with standard SFP cages. Verify your switch supports WDM transceivers and single-mode fiber before ordering. Requires LC fiber connectors on both ends; if your fiber plant uses different connectors, adapters or recertification will be needed.
Installation Notes
Single-mode fiber requires careful handling and alignment. Ensure fiber is rated for 1550 nm / 1310 nm operation and properly cleaved to avoid insertion loss exceeding 0.5 dB per connection. The bi-directional design eliminates the need for a second fiber strand, reducing installation labor and fiber lease costs on long runs. Pair units at both ends of the fiber link—do not mix with standard duplex SFP modules on the same fiber without careful wavelength planning.
