for D-Link DEM-331R DEM-331T 1.25G SFP BIDI Transceiver - 40KM Simplex

In this review the Jeirdus compatible SFP module for D-Link DEM-331T and DEM-331R is assessed for network technicians and IT managers who need reliable single-fiber, long-distance Gigabit links. The bottom line: this is a straightforward, carrier-class SFP Bidi Transceiver that delivers 1.25Gbps bidirectional optics over a single LC connector up to 40km, making it a practical replacement for OEM modules in mixed-brand environments where compatibility and tested quality matter.

Key Features

• Bidirectional 1.25Gbps: Provides simultaneous transmit and receive on a single fiber using WDM to simplify cabling for point-to-point links.
• 40km reach: Designed to link remote switches or routers over long distances without additional repeaters or amplifiers.
• Single LC connector: Uses a compact simplex LC interface that fits common SFP slots and saves rack space.
• Wavelength pair: Models use TX1310nm/RX1550nm or TX1550nm/RX1310nm so each end can be paired correctly for up and down channels.
• Compatibility lab tested: Jeirdus runs compatibility checks and codes transceivers to work with D-Link and other brands, reducing negotiation and link-up issues.
• Quality assurance: Each module is individually tested and shipped with CE and FCC compliance plus a 3 year replacement and lifetime warranty promise.

Who It's For

This module is best for network engineers and small to medium IT teams who need a cost-effective, tested replacement for D-Link DEM-331R/DEM-331T transceivers or for mixed-brand deployments where vendor-coded optics are required. It suits point-to-point backbone links, campus connections, and remote site uplinks where single-fiber routing is preferred.

Those who need multi-rate SFPs, multimode fiber links, or significantly longer distances than 40km should look elsewhere. If native vendor warranty compliance or factory OEM parts are mandatory for a support contract, verify acceptance of third-party modules before purchase.

Pros & Cons

Pros

• Direct compatibility with D-Link DEM-331T and DEM-331R form factors and coding expectations for straightforward deployment.
• Single-fiber WDM design reduces cabling and fiber strand usage in point-to-point runs.
• Individually tested modules and lab compatibility increase the chance of trouble-free operation on mixed-brand switches.
• Long 40km reach at 1.25Gbps meets many metropolitan and campus needs without extra equipment.

Cons

• Limited to 1.25Gbps and single-mode 40km operation, so it is not suitable where 10G or multimode is required.
• Third-party module may require validation with certain vendor support contracts before acceptance.

Specifications

Product Type	SFP Bidi Transceiver (pair)
Data Rate	1.25Gb/s
Standards	1000BASE-BX-U and 1000BASE-BX-D
Connector	Single LC simplex
Wavelengths	Up TX1310nm/RX1550nm; Down TX1550nm/RX1310nm
Maximum Distance	Up to 40km
Compliance & Warranty	CE, FCC; 3 year replacement and lifetime warranty

Our Verdict

The Jeirdus compatible SFP pair for D-Link DEM-331R/DEM-331T is a practical, well-tested choice for technicians who need reliable single-fiber Gigabit links up to 40km. It delivers compatibility and lab-tested interoperability at a lower cost than some OEM parts and represents good value for mixed-vendor networks, provided the 1.25Gbps rate and single-mode fiber fit the use case.

Frequently Asked Questions

Are these modules compatible with D-Link DEM-331R and DEM-331T?
Yes, they are built specifically to be compatible and are lab tested to match the coding requirements for those D-Link models.

What fiber connector and distance do they support?
They use a single LC simplex connector and support up to 40km over single-mode fiber.

Do these come with any warranty?
Yes, the modules include CE and FCC compliance and are sold with a 3 year replacement policy plus a lifetime warranty.