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TP-Link

TP-Link TL-SM321B Gigabit SFP Single-Mode Module 20km

★★★★★3.9 (23 reviews)

High-Speed Gigabit Connectivity for Extended Networks Introducing the TP-Link TL-SM321B, a high-performance 1000Base-BX WDM Bi-Directional Gigabit Single-Mode SFP Module. Designed for reliable data transmission over distances up to 20km, this module offers plug-and-play functionality, a LC simpl...

$19.99*
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*Price sourced from Amazon.com. Last updated:Jun 04, 2026.Price and availability are subject to change.

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Overview

High-Speed Gigabit Connectivity for Extended Networks

Introducing the TP-Link TL-SM321B, a high-performance 1000Base-BX WDM Bi-Directional Gigabit Single-Mode SFP Module. Designed for reliable data transmission over distances up to 20km, this module offers plug-and-play functionality, a LC simplex interface, and hot-pluggable design. Ideal for expanding your network with seamless and efficient connectivity.

  • Type: 1000Base-BX WDM Bi-Directional SFP Module
  • Distance: Up to 20km
  • TX: 1310 nm
  • RX: 1550 nm
  • Interface: LC Simplex

Key Features

Single-mode SFP Module, WDM Bi-Directional communication on a single fiber

Work with TL-SM321A as a pair and create a full-duplex gigabit path between your switches, storage devices, and server

Wavelength: Tx 1310nm, Rx 1550nm. Data Rate: 1.25Gbps. Port Type: LC Simplex.

Always keep the protective dust plug on the SFP’s optical bores until you are ready to make a connection

Compatible with all SFP ports on TP-Link product including JetStream switches, and media converter MC220L

Specifications

Module Type
SFP
Fiber Type
Single-Mode
Data Rate
1.25Gbps
Wavelength (Tx)
1310nm
Wavelength (Rx)
1550nm
Port Type
LC Simplex
Communication
WDM Bi-Directional
Maximum Distance
20km

Pros & Cons

👍 Pros

  • Supports WDM Bi-Directional communication for efficient data transfer over a single fiber strand
  • Enables the creation of a full-duplex gigabit path between compatible switches, storage devices, and servers
  • Features a Tx 1310nm, Rx 1550nm wavelength combination for specific network requirements
  • Designed to be compatible with all SFP ports on TP-Link JetStream switches and the MC220L media converter
  • Utilizes an LC Simplex port type, which is a common and straightforward connector for fiber optic connections

👎 Cons

  • Requires a compatible TL-SM321A module for bidirectional communication, necessitating a pair purchase
  • The 20km range may be overkill for shorter fiber optic runs, adding unnecessary cost to the deployment
  • Specifically designed for single-mode fiber, limiting its use in multi-mode fiber environments
  • The 1.25Gbps data rate might not meet the demands of networks requiring higher throughput
  • Compatibility is stated for TP-Link products, potentially limiting its use with other brands of networking equipment

Frequently Asked Questions

This SFP module is specifically designed for single-mode fiber, enabling long-distance data transmission over a single strand of fiber.
For full-duplex gigabit communication, this module is designed to work as a pair with the TL-SM321A, allowing bidirectional data flow over a single fiber.
The TP-Link TL-SM321B Gigabit SFP Single-Mode Module is capable of transmitting data up to 20 kilometers, suitable for extending network reach.
This module is explicitly stated to be compatible with all SFP ports on TP-Link products, including JetStream switches and the MC220L media converter.
The module operates with a transmit wavelength of 1310nm and a receive wavelength of 1550nm, facilitating WDM Bi-Directional communication.

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