11-14-2014 12:21 PM
I'm looking to connect to an ISP circuit. The fiber run is single mode and they have a 100 Base FX transceiver on their end.
I've looked up the specifications on that transceiver and it say's it should only be run on SMF.
Anyone had any success with this?
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11-14-2014 01:43 PM
You're welcome.
For a VERY short run your MIGHT be able to get a SM transceiver to work over MM fiber.
The coherent light ("single mode") from the laser that launches into much larger core of the multimode fiber (usually 50 or 62.5 microns vs 9 micron for SM and having different propagation and dispersion characteristics) may "punch through" over short distances.
I wouldn't do it in any production environment though as it would likely be unstable in the long term (and is definitely not how the equipment is designed to work).
11-14-2014 12:30 PM
The 100BASE-FX is designed for and only works with multimode fiber. This is noted in the product data sheet.
The singlemode variants of the product line are listed on the same data sheet.
Whatever variation is being used should match at both ends and use the proper fiber (MM or SM).
11-14-2014 01:28 PM
thank you for your response Marvin.
I'm just wondering if anyone has actually tried this. The ISP i'm working with claims that it works on both, though I highly doubt it.
11-14-2014 01:43 PM
You're welcome.
For a VERY short run your MIGHT be able to get a SM transceiver to work over MM fiber.
The coherent light ("single mode") from the laser that launches into much larger core of the multimode fiber (usually 50 or 62.5 microns vs 9 micron for SM and having different propagation and dispersion characteristics) may "punch through" over short distances.
I wouldn't do it in any production environment though as it would likely be unstable in the long term (and is definitely not how the equipment is designed to work).
11-14-2014 01:54 PM
Understood.. thanks again.
09-02-2016 07:55 AM
Hello George,
I know you posted this question two years ago but I have a provider now that's doing the same thing: They're using a 100Base-FX SFP over singlemode fiber. Like you, we're thinking this shouldn't work.
Did you try it? And did it work?
03-07-2019 05:16 AM
I have a situation similar to George's
The tower supplier suggested MOXA EDS-308-SS-SC-T.
I get that you might get a SM transceiver to work over a MM Fiber for a short distance but that does not apply to this situation. Here we have an optical Standard 100FX from another Vendor (MOXA) that claims to work over SM Fiber. In my case this switch is paired with a SM Fiber. What I'm looking for is a CISCO Transceiver that will Work with the MOXA Optical Standard 100FX over SM Fiber. I've provided a link to their Switch's page.
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