A Quick Guide to SFP’s

For many people the world of mall form-factor pluggable transceiver’s, or SFP’s as they are more commonly known, can be baffling.  This simple guide will take you through the different types to help explain their differences and all you need to know.

An SFP interface is widely used in computer networks and provides the devices with a modular interface that the user can easily adapt to various fibre optic and copper networking standards.

Due to its smaller size, the SFP has replaced the gigabit interface converter (GBIC) in most applications; the SFP is sometimes referred to as a Mini-GBIC.



The main types of transceivers are:

1000BASE-T SFP Copper transceiver module operates on standard Category 5 unshielded twisted-pair copper cabling of link lengths up to 100 m (328 ft).

1000BASE-SX SFP operates on legacy 50 μm MMF links up to 550 m and on 62.5 μm Fiber Distributed Data Interface (FDDI)-grade MMF up to 220 m.

1000BASE-LX/LH SFP operates on standard SMF optic link lengths up to 10km and up to 550 m on any MMF.

1000BASE-EX SFP operates on standard SMF optic link lengths up to 40km.

1000BASE-ZX SFP operates on standard SMF optic link lengths up to approximately 70km.

1000BASE-BX SFP operates on a single strand of standard SMF lengths up to 10km.


There is of course a lot more detail we can go into here, but this is not about the technical detail more of an overview.

However, a little something for the engineers out there.  The SFP was designed after the GBIC interface, and enables a higher number of transceivers per cm along the edge of a mother board than the GBIC, which is why SFP is also known as mini-GBIC.

The related Small Form Factor transceiver is similar in size to the SFP, but is soldered to the host board as a through-hole device, rather than plugged into an edge-card socket.

Problems with SFP’s

Because SFP transceivers are not standardized by any official standards body, there is only a general agreement among competing manufacturers.

This in my view is one of the more disappointing aspects of SFP’s as OEM’s want to lock you into their expensive branded units rather than allowing an open market for what is effectively a non-thinking connectivity element of the network.  In other words, they do not add value to the device other than simple connectivity. 

Why is this an issue?

I like to think of SFP’s as “nice to have branded” rather than essential.  My analogy would be your car manufacturer may like you to purchase their own branded wiper blades but in reality, most people buy generics.

If you decide to buy a switch for its functionality then the SFP’s will not be an element in this decision-making process and as someone that believes in having options I don’t think this is an area that manufacturers are being fair to their customers.

For example, a branded switch manufacturer would not expect you to purchase their own Cat 6 Patch Leads as much as they would like you to – again most people buy generic cables.

Had a previous bad experience with compatible SPF’s?

Remember, our compatibles come with a 100% guarantee and that’s lifetime so you are protected from any future OEM Firmware updates that in the passed dogged the compatible market.   And of course when you work with us you are working with the experts we only use reliable trusted manufacturers of generic SPF’s

How we can help!

In conclusion, simple as this guide is it’s still quite confusing trying to understand all the available options.  We can make this really simple you don’t need to know everything there is to know!  Let us do the work for you.  Just tell us what equipment you have and we’ll do the rest for you, original or compatible, we can supply what ever you prefer.

Call NOW and let us guide you though the best options that will work for you.

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