TP-LINK TL-SM321B-2 1000Base-BX WDM Bi-Directional SFP Module (LC Simplex, 1310/1550nm, 2km)
SKU: SM321B-2-VER2Networking › Network Accessories
฿385
Price includes 7% VATPrice updated November 2, 2026
In stock35 units2 years manufacturer's warranty
For orders placed before 12:00 on a business day; weekends excluded
GenuineFree delivery from ฿5,000Tax invoice
Dual-fiber WDM SFP module that transmits data in both directions over a single fiber optic cable, supporting up to 2 kilometers of distance, and works immediately with TL-SM321A-2
Key features
- Transmits data in both directions over a single fiber optic cable
- Supports up to 2 kilometers of distance
- Works immediately with TL-SM321A-2
- Supports DDM for real-time status monitoring
- Designed for hot swapping
Product description
The TP-Link TL-SM321B-2 module is designed to work with the TL-SM321A-2 module to create a Gigabit network connection over a single fiber optic cable, with a maximum distance of 2 kilometers, using WDM (Wavelength Division Multiplexing) technology to transmit data in opposite directions through different wavelengths (TX: 1310 nm, RX: 1550 nm) on a Single-Mode fiber optic cable with a size of 9/125 μm, reducing cable installation costs and improving network efficiency in organization networks. The module supports hot swapping and features DDM (Digital Diagnostic Monitoring) for real-time monitoring of operational status such as data transmission rate, voltage, and temperature. Compatible with switches in the T3700, T2700, T2600, T2500, T1700, T1600, T1500, 2/3/5 Series, and MC220L series.
More features
- Supports SFP-MSA standard, compatible with multiple device models
- Uses wavelengths of 1310 nm (TX) and 1550 nm (RX)
- Supports operation in temperatures from 0–70 °C
- Compact size, lightweight, easy to install
- Uses 3.3V power, energy efficient
Pros and limitations
Pros
- Uses a single fiber optic cable, reducing cabling costs.
- Supports transmission distances up to 2 kilometers.
- Features DDM for real-time status monitoring.
- Designed for hot swapping without requiring system shutdown.
- Supports SFP-MSA standard, compatible with multiple device models.
Limitations
- Must be used only with the TL-SM321A-2 module.
- Does not support operation beyond 2 km, even in V3 or V4 versions that claim 10 km or 20 km. This information is not consistent with this model.
Who it is for
Ideal for users who need to extend network connectivity over long distances between data centers, offices, or workstations using a single fiber optic cable to save costs and improve data transmission efficiency.
Connectivity
LC Connector
Specifications (31)
- Brand
- TP-LINK
- Model
- TL-SM321B-2
- Weight
- Approx. 20g
- SFP-MSA
- Yes
- Data Rate
- 1.25 Gbps
- Port Type
- LC Simplex
- Cable Type
- Single-Mode Fiber
- Fiber Type
- 9/125 μm Single-Mode
- Application
- Gigabit Ethernet, Fiber Optic Networking, Long-Haul Connectivity
- Form Factor
- SFP
- Power Supply
- 3.3V
- Product Type
- SFP Module
- Certification
- FCC, CE
- Compatibility
- TL-SM321A-2, T3700 Series, T2700 Series, T2600 Series, T2500 Series, T1700 Series, T1600 Series, T1500 Series, 2/3/5 Series Switches, MC220L
- Hot Swappable
- Yes
- Wavelength RX
- 1550 nm
- Wavelength TX
- 1310 nm
- Connector Type
- LC
- Interface Type
- LC Simplex
- Package Content
- SFP Module TL-SM321B-2, Installation Guide
- Max Cable Length
- 2 KM
- Storage Humidity
- 5–90% RH, Non-Condensing
- Safety & Emission
- FCC, CE
- Transmission Mode
- Bi-Directional WDM
- Operating Humidity
- 10–90% RH, Non-Condensing
- Storage Temperature
- -40–85 °C (-40–185 °F)
- Environmental Rating
- Industrial Grade
- Operating Temperature
- 0–70 °C (32–158 °F)
- Dimensions (W x D x H)
- 2.2 x 0.6 x 0.5 in (55.4 x 14.6 x 12.9 mm)
- Standards and Protocols
- IEEE 802.3z, TCP/IP
- Digital Diagnostic Monitoring (DDM)
- Yes
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 switch models is the TL-SM321B-2 module compatible with?
This module works with switches in the T3700, T2700, T2600, T2500, T1700, T1600, T1500, 2/3/5 Series, and MC220L series that support SFP-MSA, and must be used with the TL-SM321A-2 module to establish a full-duplex connection
Can this module be used with the TL-SM321A-2?
Yes, the TL-SM321B-2 and TL-SM321A-2 modules are designed to work together, with the B module using a wavelength of 1310 nm and the A module using 1550 nm to transmit data in opposite directions over the same cable.
Yes, this module supports real-time status monitoring
Yes, this module supports DDM (Digital Diagnostic Monitoring) as per the SFF-8472 standard, allowing real-time monitoring of values such as data rate, voltage, temperature, and optical power
Can this module be used with Multimode fiber optic cable?
No, this module is designed exclusively for 9/125 μm Single-Mode fiber optic cables. Using Multimode fiber will not allow effective signal transmission.
Yes, this module supports hot swapping
Yes, this module supports hot swapping, allowing it to be removed or installed without shutting down the network system, reducing downtime
Does this module support distances longer than 2 km?
No, this module supports a maximum distance of 2 kilometers as specified on the TP-Link website. Versions V2 and V3 may claim distances up to 10 km or 20 km, but this information does not apply to the TL-SM321B-2 model
Must I use a paired module to operate?
Yes, the TL-SM321B-2 module must be used with the TL-SM321A-2 module to enable full-duplex communication over a single fiber optic cable. Module B transmits at 1310 nm and receives at 1550 nm.
What is the weight of this module?
Approximately 20 grams. Compact size, easy to install, and requires minimal space on the switch or network device.
Is it in stock?
The TP-LINK TL-SM321B-2 1000Base-BX WDM Bi-Directional SFP Module (LC Simplex, 1310/1550nm, 2km) is in stock and ready to ship. 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). Order online at store.gist.co.th or contact our sales team at 092-251-4017.
How much does it cost?
The price is ฿385 (including 7% VAT). It is in stock and ready to ship. Business customers can request a quotation at sales@gist.co.th.
How long is the warranty?
Warranty period: 2-year warranty (manufacturer's terms). 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
2-year warranty
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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Price
฿385