You've got a gigabit link to run but only one fiber strand available. The TL-SM321B-2 handles both directions on that single strand using WDM bi-directional technology. Drop it into any SFP-MSA compliant port, connect your 9/125μm single-mode fiber, and you're transmitting. Tx at 1310nm, Rx at 1550nm. Hot-swappable — no downtime while you swap modules. DDM means you watch signal levels from your switch's management interface instead of guessing. Runs 0 to 70°C, so it'll sit happily in a server room or a dusty rack behind the shop. One strand, both ways, sorted
| brand | TP-LINK |
| model | TL-SM321B-2 |
| type | SFP Module |
| standard | 1000BASE-BX |
| wavelength_tx | 1310nm |
| wavelength_rx | 1550nm |
| fiber_type | 9/125μm Single-Mode |
| max_cable_length | 10km (per hardware spec); 2km typical (per product summary) |
| data_rate | 1.25 Gbps |
| port_type | LC Simplex |
| ddm | Yes |
| hot_swappable | Yes |
| power_supply | 3.3V |
| operating_temperature | 0–70°C (32–158°F) |
| storage_temperature | -40–85°C (-40–185°F) |
| operating_humidity | 10–90% RH, non-condensing |
| storage_humidity | 5–90% RH, non-condensing |
| certifications | FCC, CE |
