Description
TP-Link TL-SM321A-2 Gigabit WDM Bi-Directional SFP Module
The TP-Link TL-SM321A-2 is a 1000Base-BX WDM (Wavelength Division Multiplexing) bi-directional SFP module that transmits and receives over a single strand of single-mode fibre. With a TX wavelength of 1550nm and RX of 1310nm, it pairs with the complementary TL-SM321B-2 (TX 1310nm / RX 1550nm) to deliver full-duplex Gigabit connectivity over just one fibre run — halving your cabling costs on point-to-point links up to 2km.
Key Features
- 1000Base-BX WDM BiDi — full-duplex Gigabit over a single fibre strand
- TX: 1550nm / RX: 1310nm — pairs with TL-SM321B-2 at the remote end
- Up to 2km transmission distance over 9/125μm single-mode fibre (SMF)
- LC Simplex connector — standard, widely available termination
- Digital Diagnostic Monitoring (DDM) — real-time optical performance visibility
- Hot-swappable — insert or remove without powering down the host device
- SFP-MSA compliant — compatible with most SFP-capable switches and media converters
- 1.25Gbps data rate, 3.3V power supply
Use Cases
-
Point-to-point fibre links — connect two switches or media converters over a single SMF strand, saving one fibre run per link
-
Security and surveillance networks — extend Gigabit connectivity between buildings or floors where copper cabling is impractical
-
Campus and enterprise networks — cost-effective fibre uplinks where existing single-strand fibre infrastructure is already in place
-
ISP and telco last-mile — BiDi SFPs are commonly used in FTTN and point-to-point fibre distribution applications
Specifications
| Specification |
Detail |
| Model |
TL-SM321A-2 |
| Standard |
1000Base-BX (IEEE 802.3z), TCP/IP |
| TX Wavelength |
1550nm |
| RX Wavelength |
1310nm |
| Data Rate |
1.25Gbps |
| Max. Cable Length |
2km |
| Fibre Type |
9/125μm Single-Mode Fibre (SMF) |
| Connector |
LC Simplex |
| DDM |
Supported |
| Hot Swappable |
Yes |
| SFP-MSA Compliant |
Yes |
| Power Supply |
3.3V |
| Operating Temperature |
0–70°C |
| Storage Temperature |
-40–85°C |
| Operating Humidity |
10–90% RH, Non-Condensing |
| Certifications |
FCC, CE |
| SKU / Barcode |
TL-SM321A-2 / 6935364072933 |
| Weight |
0.06kg |
Pairing Note
The TL-SM321A-2 (TX 1550nm / RX 1310nm) must be paired with the TL-SM321B-2 (TX 1310nm / RX 1550nm) at the opposite end of the fibre link. Using two modules of the same type will not establish a connection.
Frequently Asked Questions
What is a BiDi SFP module?
A BiDi (bi-directional) SFP uses WDM technology to transmit and receive on different wavelengths over a single fibre strand. This allows a full-duplex Gigabit link using only one fibre run instead of two, reducing cabling costs and simplifying infrastructure.
What module do I need at the other end?
You must use the complementary TL-SM321B-2 (TX 1310nm / RX 1550nm) at the remote end. The wavelengths must be opposite — one end transmits at 1550nm while the other receives at 1550nm, and vice versa.
Is the TL-SM321A-2 compatible with third-party switches?
Yes. The TL-SM321A-2 is SFP-MSA compliant, meaning it is designed to work with any switch or media converter that accepts standard SFP modules. Compatibility with specific third-party devices should be verified with the switch manufacturer.
What does DDM (Digital Diagnostic Monitoring) do?
DDM allows you to monitor real-time optical parameters — such as TX power, RX power, temperature, and voltage — directly from a compatible switch’s management interface. This is useful for diagnosing fibre link issues without physical inspection.
Can I hot-swap this module?
Yes. The TL-SM321A-2 is hot-swappable, so you can insert or remove it from a compatible SFP port without powering down the host switch or device.
Does it ship Australia-wide?
Yes. CCTV Guru ships the TL-SM321A-2 Australia-wide from local stock.
