TP-Link Omada Gigabit WDM Bi-Directional SFP Module 2 km, 1310 nm TX / 1550 nm RX

TP-Link Omada 1000Base-BX WDM Bi-Directional SFP Module (TL-SM321B-2) - 5 Years Local Warranty

The TL-SM321B-2 is the "B" half of TP-Link's 2 km bi-directional Gigabit pair. It transmits on 1310 nm and receives on 1550 nm — the mirror of the TL-SM321A-2 — and the two together carry a full-duplex Gigabit link over one strand of single-mode fibre, for on-site runs up to 2 km.

Both Directions on a Single Strand

Conventional duplex optics consume two fibre strands per link. A WDM bi-directional pair puts transmit and receive on the same strand at different wavelengths, separated optically at each end. Where an inter-building bundle is already fully patched, or strands are leased and billed individually, that halving is often what allows a link to be added without new civil works. The connector is LC simplex, matching the single-strand design.

Two Kilometres of On-Site Reach

TP-Link publishes a maximum cable length of 2 km over 9/125 µm single-mode fibre, at the full 1.25 Gbps data rate under IEEE 802.3z. TP-Link describes the pair as creating on-site gigabit fibre communication — campus, industrial estate and neighbouring-block distances. For longer hops the 20 km TL-SM321A and TL-SM321B are the correct family; the optical budgets differ, so the families should not be mixed on one link.

Always Ordered With a TL-SM321A-2

The two ends of a WDM link are not interchangeable. TP-Link specifies this module is designed to work in a pair with the TL-SM321A-2: the B-2 transmits 1310 nm and receives 1550 nm, the A-2 does the reverse. One of each per link. Two B-2 modules facing each other will never establish a link, whatever the switch configuration, because the wavelengths do not meet.

DDM per SFF-8472, MSA Compliance and Hot Swapping

The module incorporates Digital Diagnostic Monitoring per the SFF-8472 standard, so a host switch can read live optical transmit and receive power, temperature and supply voltage — turning a degrading connector or splice into a measurable trend rather than a sudden outage. It is SFP-MSA compliant and hot-swappable, seating in any standard Gigabit SFP cage and replaceable without powering the switch down. It draws 3.3 V from the host and measures 55.4 x 14.6 x 12.9 mm.

Ideal For

Singapore campuses, industrial estates and multi-block sites connecting buildings at Gigabit speed where fibre strands are limited and the run is inside 2 km. Supplied by SourceIT with local Singapore warranty, GST invoice and project pricing on request.