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Small metal SFP transceiver with an RJ-45 port and side latch

Finisar Corporation

Finisar Corporation FCLF-8521-3 1000BASE-T Copper SFP Transceiver RJ-45 0 to 85C

SKU CH-AS6M-JVYWY MPN FCLF-8521-3

Connects Gigabit Ethernet over Cat 5 twisted pair using a hot-pluggable RJ-45 SFP transceiver compliant with IEEE 802.3 and MSA standards

  • Device TypeTransceiver
  • ProtocolsHCRP, SPP
  • Gigabit Ethernet over copper using standard Cat 5 cabling
  • Hot-pluggable SFP form factor enables tool-free installation
  • MSA compliant for multi-vendor switch compatibility
  • Operating temperature range 0 to 85 Celsius
  • RoHS-6 certified for reduced hazardous substances

Copper SFP Transceiver

The Finisar FCLF-8521-3 is a hot-pluggable SFP transceiver designed for 1000BASE-T copper connectivity. It fits standard SFP ports and uses an RJ-45 connector to link network equipment over twisted-pair cabling. The module operates across a 0 to 85C temperature range and complies with the SFP MSA and RoHS-6 requirements. It provides a single 10/100/1000Base-T port for data networking applications.

Network Upgrades and Legacy Links

This transceiver suits administrators adding copper Gigabit links to switches or routers with open SFP slots. It works where fibre is not required and Category 5 cabling is already in place. Buyers needing fibre interfaces, higher speeds such as 10G, or extended temperature ranges beyond 85C should look at other modules. The single port design also limits use in high-density aggregation scenarios.

Gigabit Copper Capacity

The module comfortably handles 10/100/1000Base-T traffic over Category 5 twisted pair up to 100 metres. It supports the IEEE 802.3 standard and allows PHY register access via I2C for advanced configuration. Headroom ends at the 1000 Mbps line rate and the 100 metre copper reach. Environments exceeding 85C or requiring multi-gigabit throughput will need different hardware.

Highlights

  • Gigabit Ethernet over copper using standard Cat 5 cabling
  • Hot-pluggable SFP form factor enables tool-free installation
  • MSA compliant for multi-vendor switch compatibility
  • Operating temperature range 0 to 85 Celsius
  • RoHS-6 certified for reduced hazardous substances

Specifications

BrandIMSOURCING
Device TypeTransceiver
ProtocolsHCRP, SPP
Shipping weight0.07 kg
Package size25 × 25 × 25 mm

Questions about this item

What type of host port is required for this SFP transceiver to operate?

It requires a standard SFP slot that supports the MSA form factor and provides the necessary I2C interface for PHY register access.

Will this 1000BASE-T module link correctly with legacy 10/100 Mbps switches using Cat5 cable?

Yes, the transceiver negotiates 10/100/1000Base-T speeds automatically over Category 5 twisted pair, so it interoperates with older Fast Ethernet equipment.

How can I verify the FCLF-8521-3 is functioning correctly after installation?

Confirm the link LED illuminates at the expected 10/100/1000 Mbps rate and use the host I2C interface to read PHY registers for link status and error counters.

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