Difference Between Finisar 1000BASE-T FCxx-8520 and 8521-3 SFPs

This article will discuss the difference between Finisar 1000BASE-T FCxx-8520/8521-3 SFPs. In addition, with the increasing demands on compatible SFPs, we highly recommend an excellent transceiver vendor, Fiberstore, to you due to the competitive price and good quality of their products. (Disclaimer: The author is employed by Fiberstore.)

Finisar’s 1000BASE-T SFP transceivers are based on the SFP Multi Source Agreement (MSA). Additionally, they are compatible with Gigabit Ethernet and 1000BASE-T standards as specified in IEEE Std. 802.3:2002. FCxx-8520/8521-3 is its product model, which includes four products, ie. FCMJ-8520-3, FCMJ-8521-3, FCLF-8520-3 and FCLF-8521-3. Generally speaking, they are both 1000BASE-T SFPs and have the similar functions. However, there are some difference between them which we can easily distinguish via the difference in the model, such as FCMJ and FCLF, the 8520 and 8521. This paper will talk about the difference between them.

Generally speaking, they are both 1000BASE-T SFPs and have the similar functions. However, there are some difference between them which we can easily distinguish via the difference in the model, such as FCMJ and FCLF, the 8520 and 8521. This paper will talk about the difference between them.

What Does 1000BASE-T Mean?

Before we begin to talk about the difference between the FCxx-8520/8521-3 SFPs, we first understand the “1000BASE-T”. 1000BASE-T is defined in IEEE802.3:2002. The “1000” in the designation refers to the transmission speed of 1000 Mbps. The “BASE” refers to BASE band signaling, indicating that only Ethernet signals are carried on the medium. The “T” represents twisted-pair copper cable (for example Cat 5). So we offer called this kind of transceivers as the

The “1000” in the designation refers to the transmission speed of 1000 Mbps. The “BASE” refers to BASE band signaling, indicating that only Ethernet signals are carried on the medium. The “T” represents twisted-pair copper cable (for example Cat 5). So we offer called this kind of transceivers as the

The “BASE” refers to BASE band signaling, indicating that only Ethernet signals are carried on the medium. The “T” represents twisted-pair copper cable (for example Cat 5). So we offer called this kind of transceivers as the

The “T” represents twisted-pair copper cable (for example Cat 5). So we offer called this kind of transceivers as the copper transceivers. If the “T” is replaced by the “X”, it represents fiber optic cable.

If the “T” is replaced by the “X”, it represents fiber optic cable.

What Is The Difference Between The FCxx-8521-3 & The FCxx-8520-3?

The FCxx-8521-3 is designed to be a 1000BASE-X compliant device that functions properly in any slot designed for optical SFP’s, with no hardware or software changes to the host system. The PHY is configured to perform 1000BASE-X auto-negotiation with the host system. The FCxx-8521-3 does not have link detection circuitry—the RxLOS pin is internally grounded. The FCxx-8520-3 is similar to the FCxx-8521-3, but the 1000BASE-X auto-negotiation is disabled. For this device to operate, auto-negotiation should also be disabled in the host system. In the FCxx-8520-3, the RxLOS pin functions as a link indicator-RxLOS

The FCxx-8520-3 is similar to the FCxx-8521-3, but the 1000BASE-X auto-negotiation is disabled. For this device to operate, auto-negotiation should also be disabled in the host system. In the FCxx-8520-3, the RxLOS pin functions as a link indicator-RxLOS is asserted when the 1000BASE-T link is lost. Typically, this device is used in systems where the host cannot determine the link status without using RxLOS as a link indicator.

What Is The Difference Between The FCMJ-8520/8521-3 & The FCLC-8520/8521-3?

The FCMJ-8520/8521-3 versions are RoHS 5/6 while the FCLF-8520/8521-3 versions are fully RoHS compliant.

What Cable Type Is Recommended For Use With The FCxx-8520/8521-3?

The FCxx-8520/8521-3 was designed to operate using standard Cat 5 cable that has been configured per IEEE802.3:2002. You can safely use Cat 5e or Cat 6 cables, as these are improved versions of Cat 5. For short cable runs, with intricate routing, stranded cable is recommended, as it is more flexible.

Better Choice of Compatible Finisar 1000BASE-T FCxx-8520/8521-3 SFPs

With a starting point of saving cost, more and more people would like to use the compatible fiber optic transceivers. When you doing some research for your purchase plan, you will find the market full of manufacturers and vendors with a wide range of options for compatible transceivers of the well-known brands (such as Cisco, HP, Finisar, or Dell). It is really a headache choosing the best compatible SFPs that can fully satisfy your demands. We can really only compare the price and shipping time in the ocean of the compatible transceivers.

For a better choice of the compatible SFPs of the Finisar 1000BASE-T SFPs, we highly recommend you get the Fiberstore NEW Finisar FCxx-8520/1-3 Compatible 1000BASE-T SFP Transceiver Module. It is low cost, high quality, and they provide excellent service. In addition, compatible transceivers of other brands can also be found in Fiberstore. You can save more time searching for a good vendor or good compatible transceivers. Try Fiberstore to get the best experience.

This was a guest post by Peter Adams, an engineer with Fiberstore. Fiberstore is in the field of fiber optic and data communication.