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FCLF-8521-3 is an industrial-grade 10/100/1000BASE-T SFP copper transceiver module that features low power consumption, a fully metallic enclosure to reduce EMI, and a 100-meter transmission range over Cat 5 cable in extreme temperatures from -40°C to +85°C.
| Finisar Part Number | FCLF-8521-3 | Vendor Name | LINK-PP |
| Part Status | Active | Form Factor | SFP SGMII |
| Max. Data Rate | 1.25G | Max. Cable Distance | 100m |
| Media | Cat 5 | Connector | RJ-45 |
| RX_LOS | Yes | DOM Support |
No |
| Operating Temperature Range | -40 to 85°C | Protocols |
SFP MSA Compliant, IEEE Std 802.3 |
Finisar FCLF-8521-3 Compatible LINK-PP module is an industrial-grade copper transceiver module built for reliable short-range networking in harsh environments. It combines flexible data speed matching, low power consumption, and a rugged design to deliver stable copper connections.
This module allows technicians to read out vital data directly from the physical layer IC inside the transceiver via a standard 2-wire serial bus. This internal access makes checking connection baselines and troubleshooting physical link issues much simpler. It gives network operators a clear way to see what is happening at the very base of the copper link.
The module supports full 1000BASE-T gigabit operation when plugged into host switch systems using a standard SERDES interface. For older or multi-speed systems, it can automatically scale down to 10/100/1000Mbps data rates when working with an SGMII interface. This makes it incredibly easy to link different generations of hardware together inside the same equipment rack.
Designed to bridge local distances easily, this transceiver maintains reliable data transmissions up to 100m using standard Cat 5 network cables. It is built to keep data moving steadily over this distance even while facing harsh industrial heat or cold. This reach is perfect for connecting separate machinery stations across a factory floor without losing signal quality.
Equipped with a standard RJ45 connector, the module allows you to plug regular copper patch cords right into an open SFP slot. The connector housing is fully metallic, which protects the signal from electromagnetic noise and stops data corruption. It provides a simple, plug-and-play way to make high-density switch ports compatible with traditional Ethernet wires.
The Finisar FCLF-8521-3 Compatible LINK-PP meets top industry standards, carrying official certifications like ISO 9001, CE, RoHS, and FCC to ensure safety and quality.
Each module undergoes rigorous physical hardware and signal integrity testing to guarantee steady, long-term operation in challenging network environments.
These global safety and environmental approvals verify that the transceiver is built using eco-friendly, lead-free processes that match strict manufacturing guidelines.
Broad hardware validation ensures this module works reliably across a wide variety of industrial switch and router platforms without causing link dropouts.
Every copper SFP module undergoes strict quality checks to verify hardware stability before deployment, and you can learn more through the LINK-PP Test Support Center.
Verify precise voltage levels and current draw across all ports.
Analyze signal waveform integrity to prevent data distortion over copper cables.
Measure data packet loss to guarantee flawless, mistake-free network transmissions.
Validate steady signal operation under extreme environmental heat and cold.
We secure each transceiver module for safe transit. Every shipment undergoes careful handling to protect your physical hardware.
Sealed in anti-static packaging to prevent electrical damage.
Shock-resistant boxing prevents physical impact damage.
Orders are verified and processed rapidly for prompt transit.
Dependable worldwide shipping via trusted global carriers.
Using this FCLF-8521-3 hot-swappable copper SFP module is entirely plug-and-play. Just insert the unit into your switch, secure the metallic latch, and connect your copper line to establish an immediate link, allowing easy on-site maintenance without interrupting the rest of your active network.
LINK-PP offers end-to-end technical support, from pre-sales consultation to post-deployment assistance, ensuring smooth integration and reliable network performance.
Professional guidance to help you select the optimal FCLF-8521-3 module for your network design and application needs.
Validated compatibility with LINK-PP switches and other mainstream networking platforms for seamless deployment.
Comprehensive step-by-step guidance for installation, configuration, and initial setup, ensuring accurate deployment and reliable, stable operation from the start.
Ongoing technical support throughout the product lifecycle, delivering long-term stability for enterprise and carrier-grade networks.
LINK-PP provides after-sales support for the smooth deployment and reliable operation of the optical modules.
15-day no-reason return and refund
Free replacement for dead-on-arrival (DOA) or defective items within the initial period
Free repair services for manufacturing defects throughout the warranty period
Warranty exclusions and conditions apply
| Pictures | ID# | Description | Price | Stock | Add to Cart |
Q: We are connecting legacy 100Mbps IP cameras to an SFP port on our main switch — will this module support 100M auto-negotiation? By V***e on 2026-03-14
A: Yes, when plugged into host systems supporting an SGMII interface, it seamlessly auto-negotiates across 10Mbps, 100Mbps, and 1000Mbps speeds. By admin on 2026-03-15
Q: We need to hook up a remote office terminal located 85maway — can this copper module handle that distance over regular Cat5? By B***l on 2026-01-11
A: Yes, it complies with 1000BASE-T standards to deliver stable gigabit connections over standard Cat5 copper cabling up to 100m (328ft). By admin on 2026-01-12
Q: We need to replace a failed transceiver in an active rack without powering down our core switch. Is this module safe for live hot-swapping? By L***t on 2025-11-07
A: Yes, it features a standard hot-pluggable SFP footprint, allowing you to insert or remove it safely without interrupting active switch operations. By admin on 2025-11-08
Q: We have severe electrical noise on our shop floor from heavy motor drives; will this transceiver drop packets due to interference? By D***n on 2025-08-29
A: No, its fully metallic enclosure provides excellent shielding against electromagnetic interference (EMI) to ensure clean, uninterrupted data transmission. By admin on 2025-08-30
Q: We are deploying telecom gear in northern Canada where winter temperatures drop below -30°C. Can this handle freezing outdoor cabinets? By L***n on 2025-04-21
A: Absolutely, this industrial-grade module is rated for extreme operating case temperatures ranging from -40°C all the way up to +85°C. By admin on 2025-04-22
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