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Can You Build a Fiber Test Kit On a Budget?
An anonymous reader writes "Have any Slashdot readers hacked together cheap test kits for fiber optic cable? More and more IT infrastructure is using multimode and single mode fiber optic cabling. Commercial test equipment is extremely expensive, running the gamut from a few hundred dollars for a basic light source, to tens of thousands for an OTDR. What equipment do you consider essential to your fiber kit? Is there a way to save costs when it comes to fiber test equipment? It is worth it to do so?"
Depends on what you need to do.
There are many different tests you can do on fiber. A basic college course will teach you that.
Do you just want to know if the fiber is not "broken"? a LED and a phototransister can do that.
Want to know if the fiber is the correct mode, optimized for the wavelength of the led, or can support multimode and run parametric tests on the fiber, gee, that gets more expensive.
Its the same for the DIY ethernet cable testers too.
Want to test continuity? a 5$ multimeter will do that.
Want to determine if the cable meets spec? You need better equipment.
Better Equipment GENERALLY equals better [test] results. [ yes, a lot can depend on the skill of the tech operating said equipment too].
"running the gambit" I don't think it means what you think it means.
OMG! Wau!
Two Media converters. If you can run ethernet over it, it's good.
That's true but only to a certain extent.
It is possible that 1Gig ethernet will work fine on a cable that will not work or has a high error rate at 10Gig.
You also will not be able to determine if a long run of single mode fiber has a multi mode patch in the middle of it (OTDR is the only thing that might give you that info).
An Optical Power Meter is your best investment. That along with a good cleaning kit will give you the best results. A lot of "bad" fibers can be traced back to dirty connectors. _Always_ clean the fiber before plugging it into an interface - it is much easier to clean the fiber than it is to clean interface optics that have been contaminated by a dirty connector end.
Beyond that if this is for in-house work just plan on using your fastest interface as a tester during downtime - setup the interface to expect loopback and put a short loopback patch at the far end. Run data through the cable and check for errors.
Or as the parent said get a couple of cheap O/E converters for field work - not as good as a fast interface but better than a power meter alone.
I friggin love this site. And here's about as cheap as you're gonna get. Though it won't exactly test your landlines.
http://www.electronickits.com/kit/complete/fibe/ck1500.htm
Raging in an online forum won't do anything for the world around you. To see change, you must take action.
You can get these used on eBay all day long for a few hundred dollars for the entire set (search terms: "fiber test*" "fiber patch*" "fiber splice*"). You may have to watch a few days for a bargain, but I'm constantly amazed at how often high-quality fiber test gear goes for a song on eBay. Purchase only name-brand gear, such as Fluke, Noyes, Microtest, TestUM, etc. (You can learn the name brands by looking at new-equipment listings at places like CDW).
There are many tutorials on the web showing how to use these tools, most from equipment vendors themselves, and some are even high quality video presentations. A useful starting point is http://fiberu.com/ (although it's become less useful since Fluke took it over).
The mini-maglite will instantly identify any fiber -- the light will be clearly visible at the far end of even a thousand-foot run. If high-power IR lasers are in use on the network, be careful to be wearing fiber goggles whenever looking at fiber ends, even at your own white light. You can't tell when a fiber is energized with high-power IR, since it's invisible.
The power meter lets you measure the light loss through a fiber path, which when correctly interpreted will give you performance information. Get one that reads tenths of a microwatt, and that also directly displays dB loss from a reference signal. If you know the installed fiber specifications (you can read these off the fiber jacket), you can compute the available bandwidth based on fiber length.
The fiberscope reveals otherwise-invisible defects in a connector so that you don't spend hours trying to make an unworkable connection work. Again, be sure you're wearing laser goggles if you don't have both ends of a fiber in your hands. Magnifying harmful IR radiation is very dangerous.
For routine work you don't need an OTDR. Besides measuring the length of a fiber, an OTDR will locate defects along a fiber span so you can locate and repair them. If you're not repairing cable, or splicing it, an OTDR is overkill. Fiber installers have such gear, and they'll be happy to use theirs on your network for a fee when you need that capability.