TP-Link SM321A-VER3.3 | 1000Base-BX WDM Bi-Directional SFP Module (1550nm TX / 1310nm RX) - 20KM
SKU: SM321A-VER3.3Networking › Network Accessories
Please enquire before ordering
The distributor has not yet confirmed the latest price and availability (last checked Aug 14, 2026)
092-251-4017Awaiting stock confirmationManufacturer's warranty
GenuineFree delivery from ฿5,000Tax invoice
Bi-Directional SFP module for Gigabit networks using Single-Mode fiber optic cable, supporting a maximum distance of 20 kilometers by transmitting and receiving data using different wavelengths over a single fiber
Key features
- Supports a maximum distance of 20 kilometers
- Uses a single fiber (Single-Mode) for simultaneous TX/RX via WDM
- TX wavelength: 1550 nm, RX wavelength: 1310 nm
- Supports DDM for real-time status monitoring
- Designed for Hot Swappable installation, easy to install
Product description
The TP-Link SM321A-VER3.3 module is a WDM Bi-Directional network connectivity device that supports the IEEE 802.3z standard, enabling simultaneous data transmission and reception over a single fiber optic cable using different wavelengths—TX at 1550 nm and RX at 1310 nm—greatly reducing fiber cabling costs. It supports a maximum distance of up to 20 kilometers on 9/125 μm Single-Mode fiber. This module works seamlessly with TP-Link devices that support SFP, such as switches, range extenders, and routers, and features DDM (Digital Diagnostic Monitoring) for real-time monitoring of operational status, including temperature, transmit and receive power levels, and current, allowing network administrators to accurately track module health.
More features
- Complies with SFP-MSA standard
- Compatible for use as a pair with TL-SM321B
- Supports wide operating temperature range of 0–70 °C
Pros and limitations
Pros
- Transmits data up to 20 kilometers using a single fiber strand.
- Uses WDM technology to reduce fiber cabling costs.
- Supports DDM for real-time status monitoring immediately after installation.
- Easy installation with Hot Swappable capability.
- Complies with SFP-MSA standards, ensuring compatibility with multiple device models.
Limitations
- Must be used with TL-SM321B module to achieve full performance.
- Not supported for use over distances shorter than 2 kilometers (if using other models).
Who it is for
Ideal for organizations needing to extend long-distance networks between buildings or connect data centers using a single fiber to reduce fiber cabling costs.
Connectivity
LC Connector
Specifications (24)
- Data Rate
- 1.25 Gbps
- Port Type
- LC Simplex
- Cable Type
- Single-Mode Fiber
- Fiber Type
- 9/125 μm Single-Mode
- Application
- Gigabit Ethernet, Long-Haul Fiber Networking
- DDM Support
- Yes
- Module Type
- SFP Module
- Power Supply
- 3.3 V
- Compatibility
- Works with TL-SM321B as a pair
- Hot Swappable
- Yes
- Connector Type
- LC Simplex
- Wave Length RX
- 1310 nm
- Wave Length TX
- 1550 nm
- Max Cable Length
- 20 KM
- Storage Humidity
- 5–90% RH, Non-Condensing
- Transmission Mode
- WDM Bi-Directional
- Operating Humidity
- 10–90% RH, Non-Condensing
- SFP-MSA Compliance
- Yes
- Storage Temperature
- -40–85 °C (-40–185 °F)
- Operating Temperature
- 0–70 °C (32–158 °F)
- Dimensions (W x D x H)
- 2.2*0.6*0.5 in (55.4*14.6*12.9 mm)
- Standards and Protocols
- IEEE 802.3z, TCP/IP
- Digital Diagnostic Monitoring
- Yes (SFF-8472 compatible)
- Safety and Emission Standards
- FCC, CE
Datasheets and manuals straight from the manufacturer — select a document to open or download it.
13 questions
Frequently asked questions about this product
Compiled from manufacturer information
Which model must the SM321A-VER3.3 module be used with?
This module must be used with the TP-Link TL-SM321B to enable complete bidirectional data transmission and reception over a single fiber, as both models work together using WDM Bi-Directional technology
Can this module be used with Single-Mode fiber?
Yes, this module is designed exclusively for use with 9/125 μm Single-Mode fiber optic cable and supports a maximum distance of 20 kilometers
Can the module's operational status be monitored?
Yes, through the DDM (Digital Diagnostic Monitoring) feature compliant with the SFF-8472 standard, allowing real-time monitoring of values such as temperature, transmit and receive power, and current via network management systems
Can this module be used with a general-purpose router?
It must be used with devices that support SFP ports and are compatible with WDM Bi-Directional modules, such as Omada series switches or routers specifically designed for fiber optic connectivity
How much power does this module consume?
This module operates at 3.3 V, which is the standard voltage for SFP modules, requiring no additional power supply, and functions within an operating temperature range of 0–70 °C for real-world use
What is the maximum distance supported by this module?
This module supports a maximum distance of up to 20 kilometers when used with 9/125 μm Single-Mode fiber optic cable, provided it is used in pair with the TL-SM321B module for full system operation
Is there a warranty?
No warranty information is available in the provided source, but this module is manufactured by TP-Link and is compatible with SFP-MSA-compliant devices. Contact the sales team to verify warranty terms
Can it be used immediately after installation?
Yes, this module supports Hot Swappable functionality, allowing it to be inserted into an SFP port immediately without powering down the device, and its operational status can be monitored instantly via DDM after installation.
Is it in stock?
We are confirming the latest stock and price of the TP-Link SM321A-VER3.3 | 1000Base-BX WDM Bi-Directional SFP Module (1550nm TX / 1310nm RX) - 20KM with the distributor. Please contact us before ordering at 092-251-4017 or sales@gist.co.th.
How much does it cost?
The distributor has not yet confirmed the latest price and availability. Please contact us before ordering at 092-251-4017 or sales@gist.co.th.
How long is the warranty?
The warranty follows the manufacturer's terms for each model; ask our sales team for the warranty period of this model. To make a warranty claim, call 092-251-4017 or 065-523-5262, or email sales@gist.co.th (Mon–Fri 9:00–18:00), then send the product with your order number to our head office, or bring it to the head office in person.
How long does delivery take?
Orders placed before 12:00 on a business day are delivered within 1–3 business days (Bangkok and vicinity) or 2–5 business days (other provinces). Free delivery on orders of ฿5,000 or more (a ฿150 delivery fee applies below this amount).
Is it genuine?
Genuine products sourced from distributors in Thailand, covered by the manufacturer's warranty. Full tax invoices are available.
Didn't find the answer you need?
Loading reviews…
Genuine products
Sourced from distributors in Thailand and covered by the manufacturer's warranty
Warranty period
According to the manufacturer's terms for each model
Covered by the manufacturer's warranty; you can make claims through GIST
Claims through GIST
Ship the product to our head office or bring it in person
Warranty conditions
- A receipt or other proof of purchase is required
- The product must not have been modified or altered
- Damage caused by misuse is not covered by the warranty
- To make a warranty claim, call 092-251-4017 or 065-523-5262, or email sales@gist.co.th (Mon–Fri 9:00–18:00), then send the product with your order number to our head office, or bring it to the head office in person.Head office: 554 Sky Nine Center, Floor 12A, Room 554/62, Asok-Din Daeng Road, Din Daeng Subdistrict, Din Daeng District, Bangkok 10400
More in Network Accessories
