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Small metallic SFP transceiver with an RJ-45 port

Finisar Corporation

Finisar Corporation FCLF8521P2BTL 1000BASE-T Copper SFP Transceiver

SKU CH-KWPR-1XFN3 MPN FCLF8521P2BTL

A hot-pluggable SFP transceiver providing 1.25 Gbps RJ-45 connectivity with extended temperature range from -40°C to +85°C and low 1.05 W power dissipation

  • Device TypeTransceiver
  • PortsRJ-45
  • Transfer Rate1.25 Gbps
  • Gigabit Ethernet connectivity via 1.25 Gbps RJ-45 link
  • Hot-pluggable SFP form factor enables tool-free module swaps
  • Industrial temperature rating from -40 °C to +85 °C
  • Metallic enclosure reduces electromagnetic interference in dense racks
  • Low 1.05 W typical power draw cuts operating costs

Copper SFP for Gigabit Ethernet links

The Finisar FCLF8521P2BTL is a 1000BASE-T transceiver built to the SFP MSA. It provides an RJ-45 port for copper cabling at 1.25 Gbps bi-directional data rates. Network engineers use it to add copper uplinks to switches or routers with SFP slots. The module operates across an extended case temperature range of -40°C to +85°C.

Hot-plug installation with PHY access

The transceiver inserts into any compliant SFP cage without powering down the host. A fully metallic enclosure keeps EMI low and the RJ-45 connector assembly is compact. The on-board PHY is reachable through a 2-wire serial bus, so link settings can be read or changed via I2C. Typical power draw is 1.05 W.

Distance and speed limits of 1000BASE-T

The IEEE 802.3 standard caps copper links at 100 metres over Category 5 or better cable. This module does not support fibre distances or speeds beyond 1 Gbps. Buyers needing longer reach or multi-gigabit rates must choose a different media type. RoHS compliance follows Directive 2002/95/EC and Finisar Application Note AN-2038.

Highlights

  • Gigabit Ethernet connectivity via 1.25 Gbps RJ-45 link
  • Hot-pluggable SFP form factor enables tool-free module swaps
  • Industrial temperature rating from -40 °C to +85 °C
  • Metallic enclosure reduces electromagnetic interference in dense racks
  • Low 1.05 W typical power draw cuts operating costs

Specifications

BrandFinisar Corporation
ModelFCLF8521P2BTL
Device TypeTransceiver
PortsRJ-45
Transfer Rate1.25 Gbps
Shipping weight0.05 kg
Package size94 × 69 × 15 mm

Questions about this item

How do I confirm the FCLF8521P2BTL is operating correctly after installation?

Check for link LED activity on the host port and verify a stable 1.25 Gbps connection; the module supports I2C access to the PHY for detailed diagnostics.

What is included with the FCLF8521P2BTL and what must be sourced separately?

The transceiver itself is supplied; you must provide a standard Cat5e or better RJ-45 patch cable and an SFP-compatible host slot.

Which version among the 8520, 8521 and 8522 should I select?

Choose the FCLF8521P2BTL for an extended case temperature range of -40°C to +85°C; the other models cover different temperature grades.

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