The TP-Link TL-SM321A is a 1.25Gbps, single-mode bidirectional SFP transceiver for network administrators linking switches, servers, storage, or media converters over one fiber strand. Pair it with a TL-SM321B for a full-duplex connection up to 20km, using simplex LC connectors.
Recommended For
- Home-lab and small-office network builders connecting switches, servers, or storage across a single-mode fiber run, when both endpoints support 1G SFP and the link uses the matching opposite-wavelength BiDi module.
- Installers or site owners extending a wired network between buildings or rooms where a single fiber strand is already run or is preferred; BiDi sends and receives over that strand, with a compatible module at the other end.
- TP-Link switch or media-converter owners building a compatible fiber link, especially those who want DDM readings such as optical power and temperature for basic transceiver monitoring.
- Network technicians replacing or adding a 1G BiDi optic in an existing single-mode fiber setup who can verify the host port, fiber connector, module revision, and opposite-end wavelength before installation.
Real-World Use Scenarios
- Link two switches in separate buildings or network areas over an installed single-mode fiber strand; with the matching TL-SM321B at the other end, the pair provides a full-duplex Gigabit connection without using a second strand.
- Extend a wired network to an outbuilding or remote office that already has single-mode fiber; the paired modules can carry network traffic between switches while avoiding a new copper run.
- Use a single fiber strand between a switch and a compatible media converter when the remote device or network segment needs a copper Ethernet connection; the converter provides the fiber-to-Ethernet handoff.
- Connect a remote switch that serves devices such as computers, access points, or cameras; the SFP pair forms the fiber uplink, while the switch handles the local device connections.
- Check optical power and temperature readings while diagnosing a fiber link, if the host switch supports DDM; this can help distinguish a transceiver or signal issue from other network problems.
Spec Summary
| Attribute | Value |
|---|
| Best For | Single-mode fiber links between compatible SFP-equipped network devices, with bidirectional transmission over a single fiber |
|---|
| Optical Interface And Reach | LC simplex interface for single-mode fiber, with WDM bidirectional transmission over a single fiber and a link distance of up to 20 km |
|---|
| Data Rate And Wavelength | 1.25 Gbps data rate; transmits at 1550 nm and receives at 1310 nm |
|---|
| Standards And Protocols | Complies with IEEE 802.3z and SFP-MSA; supports CSMA/CD and TCP/IP |
|---|
| Monitoring | Supports Digital Diagnostic Monitoring (DDM), compatible with SFF-8472, for real-time transceiver status including optical power and operating temperature |
|---|
| Operating Environment | Operating temperature: 0°–70° C; humidity: 10%–90% non-condensing |
|---|
| Model Identifiers | TP-Link TL-SM321A |
|---|
| Package Contents | SFP module and installation guide |
|---|
here!
