TP-Link TL-SM321A 1000Base-BX WDM Bi-Directional Gigabit Single-Mode SFP Transceiver

Single-fibre bidirectional SFP

The TL-SM321A is a 1000Base-BX WDM transceiver that sends and receives gigabit data on one single-mode fibre strand. It targets network engineers extending links between switches, storage arrays or servers up to 20 km using 9/125 µm cable. The module plugs into any SFP-MSA port and pairs with the TL-SM321B to form a full-duplex path.

Thermals and power

Operating temperature spans 0 °C to 70 °C with humidity tolerance of 10 % to 90 % non-condensing. The hot-swappable design allows insertion or removal without powering down the host device, so service interruptions are avoided. Power draw follows the SFP-MSA envelope and the integrated DDM function reports real-time temperature, bias current and optical levels for proactive monitoring.

Deciding specification

TX wavelength is 1550 nm and RX wavelength is 1310 nm, delivering 1.25 Gbps over an LC simplex connector. This wavelength pairing only works when the opposite end uses the complementary 1310 nm TX / 1550 nm RX module. Buyers who need a different wavelength plan or multimode fibre cannot use this transceiver.