Experiment With SFP Modules With This Handy Breakout

While most home networking hardware comes with network ports baked in from the factory, industrial grade gear is typically more versatile. Using standards like Small Form-factor Pluggable, or SFP, network switches can be used with a variety of transport mediums by simply swapping tranceivers in and out. These network devices typically handle the nitty gritty of transmitting Ethernet over fiber optics, and for those keen to experiment, this breakout may come in handy.

The board design comes complete with an SFP receptacle, allowing a variety of compatible receivers to be plugged in for experimentation. With the standard using differential signalling, the board carries hardware to allow the transceiver to be fed with single-ended signals instead, though a differential version is available too. The board can be used for transmitting different signals over fiber, outside just Ethernet, or used as a simple way to reprogram SFP modules via I2C. The latter can be useful to get around DRM in network switches that attempt to lock out generic transceiver modules.

It’s a useful piece of hardware for the fiber optic tinkerer and network admin alike. You might also find it useful if you’re building your own 10-gigabit network at home!

20 thoughts on “Experiment With SFP Modules With This Handy Breakout

  1. Neat! I remember making one of these nearly a decade ago for experimenting at work. I built two of my own Fibre testers using the boards I made up, they communicated over the fibre link so each end saw the stats for both ends.

  2. SFP modules are honestly little more than high speed bi directional opto couplers.
    Driving them is usually not too hard if one has a suitable single ended to bidirectional converter. (or if the chip one uses is bidirectional to start with.)

    And a lot of high speed networking SFPs have fairly low jitter, opening the door for a lot of triggering applications as long as one takes propagation delay into account.

    The main advantage of SFPs is when one combines them with some muxes and get fairly good datarates without needing to worry much about large voltage differences. Be it in HV experiments or just lightning protection. (unless one uses an SFP that isn’t using fiber, both coax (as in SMA connectors) and DAC exist on the market.)

  3. I´d like to use some SFPs to cobble some way of testing GPON equipment, or for training/demonstrations.

    Does someone has any recommendation of which model should work, or if there is compatibility problems with switches? Most of the modules I find on the web state they are for Mikrotik things but do not say if they would work with other brands …

    1. Vendor lockout is a problem. Many switch vendors only accept their own modules. I’ve experience that many times.

      My recommendation is to go for a cheap single vendor solution. My recommendation would be to get a Ubiquiti switch with SFP or SFP+ as you require and the use the Ubiquiti SFP modules. It’s the cheapest solution.

      If you are new to Ubiquiti, you’ll see they have an “edge” and “UniFi” version. The “edge” contains a full featured UI and CLI whereas the “UniFi” variant runs using their software controller and essentially contains no local UI. Even if you setup a controller there is less to play with. I would recommend you get the “edge” variant of the switch.

      Cheers, wizdude

      1. It is not the cheapest option, not by a fair bit.
        Ubiquiti’s switching offerings are more expensive than Mikrotik’s, and Mikrotik does not lock their products (admittedly, vendors like FS.com and 10Gtek will program transceivers for whatever locked platform you want). Then you can use transceivers from Mikrotik, random Amazon ones from say, 10Gtech, or FS.com transceivers. You can get a Mikrotik with SFP for as little as 40$, versus the 99$ I saw for Ubiquiti’s cheapest Edgerouter. SFP+ can be had as low as 99$. The Ubiquiti transceivers are only sold in pairs, but go as low as 8.5$ for gigabit or 19$ for 10G. 10Gtek transceivers go for as little as 17.5$ per 10G, and less than 8$ a piece for gigabit. And all that stuff is Amazon pricing, so some vendors will carry it cheaper.

        1. Since I do not need fancy features or the like, I will probably research more about the cheap options. Probably the Mikrotik ones, with common gigabit transceivers. As it is only for demonstration/training, high speeds are not necessary.

          Thanks guys.!!

        2. Where Mikrotik have always fallen down though is the Wireless (unless this has changed now? Whenever I’ve used it its been terrible) Unifi are fantastic as you can standardise on one brand for both.

  4. I wonder what speeds people will be able to get out of this. a homebrew USB or digital video setup could be interesting for getting some long distance signaling (especially if latency can be kept low). At 10GbE it could even have some interesting applications with PCIe.

    If this opens the door for QSFP experimentation in the future, then it could get even more interesting.

  5. I am new to working with optical transceivers and have an interesting project at hand. I have been reading about SFPs for quite a while now and have decided to instead buy a sort of breakout board to get started sooner. The osmocom ( https://osmocom.org/projects/misc-hardware/wiki/Sfp-breakout ) one though is out of my budget. I’m looking for a 100 MHz clock frequency and about 2-2.5 Gbps data rate from the transceiver. Any thoughts on this?

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