The TP-Link TL-SM321B-2 is a Gigabit WDM Bi-Directional SFP module engineered for high-efficiency, cost-saving fiber networking over a single strand of 9/125 μm single-mode fiber. Using WDM (Wavelength Division Multiplexing) technology, it transmits at 1310nm and receives at 1550nm, allowing full-duplex communication over a single fiber line—ideal for enterprise, campus, or building interconnects.

This module is fully SFP-MSA compliant, features Digital Diagnostic Monitoring (DDM) for real-time link performance analysis, and is hot-swappable, making it effortless to install without interrupting operations. Pair it with the TL-SM321A-2 to complete a bidirectional fiber link up to 2 km.

What’s in the Box

• TP-Link TL-SM321B-2 WDM SFP Module

• Installation Guide

Main Features

✅ WDM Bi-Directional Transceiver – Transmit at 1310 nm, receive at 1550 nm
✅ Single-Fiber Transmission – Up to 2 km using 9/125 μm SMF
✅ 1.25 Gbps Gigabit Speed – Stable high-speed data transmission
✅ LC Simplex Connector – Compact form for space-saving fiber setups
✅ Supports DDM – Real-time diagnostics and link health monitoring
✅ SFP-MSA Compliant – Compatible with a wide range of SFP slots
✅ Hot Swappable – Non-disruptive maintenance and upgrades
✅ Ideal for Use with TL-SM321A-2 – Build a cost-efficient, full-duplex link

Detailed Specifications

Data Rate

• 1.25 Gbps

Wavelength

• TX: 1310 nm

• RX: 1550 nm

Connector Type

• LC Simplex

Fiber Type

• 9/125 μm Single-Mode Fiber

Maximum Distance

• 2 km

Form Factor

• SFP

Hot Swappable

• Yes

Digital Diagnostic Monitoring (DDM)

• Supported

Standards & Protocols

• IEEE 802.3z

• TCP/IP

• SFP-MSA Compliant

Power Supply

• 3.3V

Certifications

• FCC, CE

Dimensions (W x D x H)

• 2.2 × 0.6 × 0.5 in (55.4 × 14.6 × 12.9 mm)

Environmental Conditions

• Operating Temperature: 0°C to 70°C (32°F to 158°F)

• Storage Temperature: -40°C to 85°C (-40°F to 185°F)

• Operating Humidity: 10%–90% RH, non-condensing

• Storage Humidity: 5%–90% RH, non-condensing

Warranty Information

Manufactures warrenty applied .

Brand Description

TP-Link TL-SM321B-2 is a high-performance 1000Base-BX WDM Bi-Directional SFP module designed for single-mode fiber transmission up to 2 km using LC simplex connectors. It supports Digital Diagnostic Monitoring (DDM), is MSA-compliant, and ensures reliable, high-speed Gigabit connectivity for enterprise and carrier-grade networks.

SKU

TL-SM321B-2

Practical Use Scenarios

🏢 Campus & Enterprise Fiber Uplinks – Use in high-efficiency links with limited fiber strands
🏫 Educational Networks – Cost-effective bi-directional transmission over existing fiber lines
🏠 Point-to-Point Fiber Links – Simplify setups between remote buildings
🔌 Pair with TL-SM321A-2 – Complete a two-module, full-duplex WDM link over a single fiber core

Datasheets / Downloadable Resources

📄 Datasheet

Excellence for the Australian and New Zealand Market

The TL-SM321B-2 is tailored for the ANZ market, ensuring it meets CE, FCC, and RoHS compliance standards. All units supplied locally are sourced through authorized TP-Link distributors, ensuring local warranty coverage, compliance with telecommunications standards, and reliable product support.

 FAQs

Q1. What is the compatible pair for TL-SM321B-2? (TL-SM321B-2)
The TL-SM321B-2 is designed to work with TL-SM321A-2 for full-duplex communication over a single fiber core.

Q2. How far can TL-SM321B-2 transmit data? (TL-SM321B-2)
It supports transmission up to 2 km over 9/125 μm single-mode fiber.

Q3. What type of connector is used in TL-SM321B-2? (TL-SM321B-2)
The module features a LC simplex connector, supporting WDM single-strand transmission.

Q4. Does TL-SM321B-2 support Digital Diagnostic Monitoring? (TL-SM321B-2)
Yes, the module supports DDM, enabling real-time link and hardware diagnostics.

Q5. Is TL-SM321B-2 compatible with third-party switches? (TL-SM321B-2)
Yes, it is SFP-MSA compliant, making it compatible with many third-party switches supporting SFP modules.