TP-Link SM321B-VER3.3 | 1000Base-BX WDM Bi-Directional SFP Module (1310nm TX / 1550nm RX)
SKU: SM321B-VER3.3Networking › Network Accessories
Please enquire before ordering
The distributor has not yet confirmed the latest price and availability (last checked Jun 15, 2026)
092-251-4017Awaiting stock confirmationManufacturer's warranty
GenuineFree delivery from ฿5,000Tax invoice
Dual-fiber WDM SFP module for Gigabit networks using a single fiber optic cable, supporting up to 20 km distance, and works immediately as a pair with TL-SM321A
Key features
- Transmit and receive data over a single fiber using WDM technology
- Supports up to 20 km distance on Single-Mode fiber
- Works immediately as a pair with TL-SM321A module
- Supports Digital Diagnostic Monitoring (DDM) for real-time operational status monitoring
- Hot-swappable design allows installation or removal without powering down the device
Product description
The TP-Link SM321B-VER3.3 module uses WDM (Wavelength Division Multiplexing) technology to transmit data in opposite directions over the same fiber optic cable, using different wavelengths: 1310 nm for transmission (TX) and 1550 nm for reception (RX). This reduces the number of fiber cables required, saving costs and improving long-distance network efficiency. It supports signal transmission up to 20 km using 9/125 μm Single-Mode fiber optic cable, complies with IEEE 802.3z and TCP/IP standards, and is compatible with SFP-MSA-supporting devices such as routers, switches, and media converters from TP-Link. It must be used in pairs with the TL-SM321A module to ensure full system functionality.
More features
- Compact and lightweight, measuring 55.4 x 13.7 x 12.9 mm
- Complies with SFP-MSA standard, compatible with multiple brands of equipment
- Operates at 0–70 °C and can be stored at -40–85 °C
Pros and limitations
Pros
- Reduces fiber optic cable count by half using WDM technology
- Supports up to 20 km distance, suitable for real-world long-distance applications
- Features DDM for real-time operational status monitoring
- Easy installation without powering down when replacing modules (Hot Swappable)
- Compact size saves space in the SFP slot
Limitations
- Must be used only in pair with TL-SM321A module
- Not compatible with devices that do not support WDM or SFP-MSA
Who it is for
Ideal for organizations needing to extend long-distance networks, such as between buildings or connecting data centers, using a single fiber optic cable to reduce costs and increase cable deployment flexibility
Connectivity
SFP
Specifications (21)
- Standard
- IEEE 802.3z, TCP/IP
- Data Rate
- 1.25 Gbps
- Port Type
- LC Simplex
- Cable Type
- Single-Mode Fiber
- Fiber Type
- 9/125 μm Single-Mode
- Power Supply
- 3.3 V
- Compatibility
- Works with TL-SM321A as a pair
- Hot Swappable
- Yes
- Wave Length RX
- 1550 nm
- Wave Length TX
- 1310 nm
- Max Cable Length
- 20 KM
- Storage Humidity
- 5–90% RH, Non-Condensing
- Hardware Features
- DDM, SFP-MSA, Hot Swappable
- Safety & Emission
- FCC, CE
- 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)
- 2.1×0.5×0.5 in (55.4×13.7×12.9 mm)
- Digital Diagnostic Monitoring
- Yes (DDM)
- Wavelength Division Multiplexing
- Bi-Directional WDM
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 models can the SM321B-VER3.3 module work with?
This module must be used only in pair with TP-Link TL-SM321A module to ensure complete WDM system operation, as each module transmits and receives at different wavelengths
What type of fiber optic cable is supported?
Supports only Single-Mode fiber optic cable with size 9/125 μm. Do not use with Multi-Mode cable.
How far can data be transmitted?
Supports maximum distance up to 20 km, using high-quality Single-Mode cable and 1000Base-BX compatible endpoint devices.
Does it have a status monitoring system?
Yes, this module supports Digital Diagnostic Monitoring (DDM), which enables real-time monitoring of signal level, voltage, and temperature through the network system
Does it require powering down when installed?
No, it is not necessary. This module supports Hot Swappable operation, allowing installation or removal without powering down the main device
Can it be used with devices from other brands?
Only with devices that support the SFP-MSA standard and have an SFP port with specific WDM support. If WDM is not supported, the module will not function
What is the operating temperature range?
Operates at 0–70 °C and can be stored at -40–85 °C, making it suitable for both indoor and outdoor environments
Is there a warranty?
No warranty information is available in the provided data. Contact the sales team immediately for further details
Is it in stock?
We are confirming the latest stock and price of the TP-Link SM321B-VER3.3 | 1000Base-BX WDM Bi-Directional SFP Module (1310nm TX / 1550nm RX) 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.
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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
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