{"product_id":"for-d-link-dem-331r-dem-331t-1-25g-sfp-bidi-transceiver-40km-simplex","title":"for D-Link DEM-331R DEM-331T 1.25G SFP BIDI Transceiver - 40KM Simplex","description":"\u003cp\u003eIn 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 \u003cstrong\u003eSFP Bidi Transceiver\u003c\/strong\u003e 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.\u003c\/p\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n \u003cli\u003e\n\u003cstrong\u003eBidirectional 1.25Gbps:\u003c\/strong\u003e Provides simultaneous transmit and receive on a single fiber using WDM to simplify cabling for point-to-point links.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003e40km reach:\u003c\/strong\u003e Designed to link remote switches or routers over long distances without additional repeaters or amplifiers.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eSingle LC connector:\u003c\/strong\u003e Uses a compact simplex LC interface that fits common SFP slots and saves rack space.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eWavelength pair:\u003c\/strong\u003e Models use TX1310nm\/RX1550nm or TX1550nm\/RX1310nm so each end can be paired correctly for up and down channels.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eCompatibility lab tested:\u003c\/strong\u003e Jeirdus runs compatibility checks and codes transceivers to work with D-Link and other brands, reducing negotiation and link-up issues.\u003c\/li\u003e\n \u003cli\u003e\n\u003cstrong\u003eQuality assurance:\u003c\/strong\u003e Each module is individually tested and shipped with CE and FCC compliance plus a 3 year replacement and lifetime warranty promise.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eWho It's For\u003c\/h2\u003e\n\u003cp\u003eThis 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.\u003c\/p\u003e\n\u003cp\u003eThose 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.\u003c\/p\u003e\n\n\u003ch2\u003ePros \u0026amp; Cons\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePros\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003eDirect compatibility with D-Link DEM-331T and DEM-331R form factors and coding expectations for straightforward deployment.\u003c\/li\u003e\n \u003cli\u003eSingle-fiber WDM design reduces cabling and fiber strand usage in point-to-point runs.\u003c\/li\u003e\n \u003cli\u003eIndividually tested modules and lab compatibility increase the chance of trouble-free operation on mixed-brand switches.\u003c\/li\u003e\n \u003cli\u003eLong 40km reach at 1.25Gbps meets many metropolitan and campus needs without extra equipment.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eCons\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n \u003cli\u003eLimited to 1.25Gbps and single-mode 40km operation, so it is not suitable where 10G or multimode is required.\u003c\/li\u003e\n \u003cli\u003eThird-party module may require validation with certain vendor support contracts before acceptance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003ctable\u003e\n \u003ctr\u003e\n\u003ctd\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eSFP Bidi Transceiver (pair)\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eData Rate\u003c\/td\u003e\n\u003ctd\u003e1.25Gb\/s\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eStandards\u003c\/td\u003e\n\u003ctd\u003e1000BASE-BX-U and 1000BASE-BX-D\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eConnector\u003c\/td\u003e\n\u003ctd\u003eSingle LC simplex\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eWavelengths\u003c\/td\u003e\n\u003ctd\u003eUp TX1310nm\/RX1550nm; Down TX1550nm\/RX1310nm\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eMaximum Distance\u003c\/td\u003e\n\u003ctd\u003eUp to 40km\u003c\/td\u003e\n\u003c\/tr\u003e\n \u003ctr\u003e\n\u003ctd\u003eCompliance \u0026amp; Warranty\u003c\/td\u003e\n\u003ctd\u003eCE, FCC; 3 year replacement and lifetime warranty\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eOur Verdict\u003c\/h2\u003e\n\u003cp\u003eThe 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.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eAre these modules compatible with D-Link DEM-331R and DEM-331T?\u003c\/strong\u003e\u003cbr\u003eYes, they are built specifically to be compatible and are lab tested to match the coding requirements for those D-Link models.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat fiber connector and distance do they support?\u003c\/strong\u003e\u003cbr\u003eThey use a single LC simplex connector and support up to 40km over single-mode fiber.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDo these come with any warranty?\u003c\/strong\u003e\u003cbr\u003eYes, the modules include CE and FCC compliance and are sold with a 3 year replacement policy plus a lifetime warranty.\u003c\/p\u003e","brand":"Jeirdus","offers":[{"title":"Default Title","offer_id":48636220539099,"sku":"B07D5DN1VF","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0724\/1043\/1707\/files\/51N6ZTJxyuL._AC_6918d38d-85ac-46be-8e50-192c63b8c77a.jpg?v=1778541418","url":"https:\/\/gearmusthave.com\/products\/for-d-link-dem-331r-dem-331t-1-25g-sfp-bidi-transceiver-40km-simplex","provider":"GearMustHave","version":"1.0","type":"link"}