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Single mode fiber cable: which SFP module? (lemmy.world)

submitted 4 months ago by peregus@lemmy.world to c/homelab@lemmy.ml

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My Internet provider just installed a 2,5/1Gbps Internet connection and I've asked the guys to run a couple of their fiber to connect my router (HP Prodesk with OPNsense) to my server. I didn't know that the fiber is single mode and all the SFP+ sold used now seems to be all for multi mode fiber (www.bargainhardware.co.ukfor example). The cable is about 30m, can I use a 810nm SFP+ or is it definitely better to use a 1310nm?

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[–] peregus@lemmy.world 1 points 4 months ago (1 children)

Thanks for your precision! To the ONT arrives a single fiber with a SC/APC connector, but this is not a problem since I will be using the ONT provided and use the 2,5Gb copper port to connect it to OPNsense (looking for a 2,5 Gb PCI card). The 2 fiber that I've asked them to run (from OPNsense to server) are terminated with the same SC/APC connectors and I was thinking about using this SC female/female adapter and this SC/APC to LC cable that I've just realized that are still APC...I'll have a look if there are SC/APC to LC/UPC cables

As for that xcvr, please note that it’s an LRM, or Long Range Multimode xcvr. Would it probably work at 30 meters? Probably. But an LR xcvr that is single mode 1310 nm would be ideal.

Is it a LRM? Damn, I didn't realized since I've filtered for single mode. If the filter doesn't work, I've no idea which is LR. Would you be so gentle to point to a cheap one for single mode finer?

[–] litchralee@sh.itjust.works 0 points 4 months ago (1 children)

I've only looked briefly into APC/UPC adapters, although my intention was to do the opposite of your scenario. In my case, I already had LC/UPC terminated duplex fibre through the house, and I want to use it to move my ISP's ONT closer to my networking closet. That requires me to convert the ISP's SC/APC to LC/UPC at the current terminus, then convert it back in my wiring closet. I hadn't gotten past the planning stage for that move, though.

Although your ISP was kind enough to run this fibre for you, the price of 30 meters LC/UPC terminated fibre isn't terribly excessive (at least here in USA), so would it be possible to use their fibre as a pull-string to run new fibre instead? That would avoid all the adapters, although you'd have to be handy and careful with the pull forces allowed on a fibre.

But I digress. On the xcvr choice, I don't have any recommendations, as I'm on mobile. But one avenue is to look at a reputable switch manufacturer and find their xcvr list. The big manufacturers (Cisco, HPE/Aruba, etc) will have detailed spec sheets, so you can find the branded one that works for you. And then you can cross-reference that to cheaper, generic, compatible xcvrs.

[–] peregus@lemmy.world 1 points 4 months ago (1 children)

Although your ISP was kind enough to run this fibre for you, the price of 30 meters LC/UPC terminated fibre isn’t terribly excessive (at least here in USA), so would it be possible to use their fibre as a pull-string to run new fibre instead? That would avoid all the adapters, although you’d have to be handy and careful with the pull forces allowed on a fibre.

The problem is the installation of the connectors. They've welded the fiber the SC/APC pigtails, I wouldn't be able to do that.

The big manufacturers (Cisco, HPE/Aruba, etc) will have detailed spec sheets, so you can find the branded one that works for you. And then you can cross-reference that to cheaper, generic, compatible xcvrs.

That would be very very generous of you; in the fiber section I'm pretty ignorant and I'm worried to purchase wrong items 🙈

[–] litchralee@sh.itjust.works 1 points 4 months ago (1 children)

I quickly looked up the HPE/Aruba transceiver document, and starting on page 61 is the table of SFP+ transceivers, specifically describing the frequency and mode. At least from their transceivers, J9151A, J9151E, JL749A, and JL783A would work for your single-mode, 1310 nm needs.

You will have to do additional research to find generic parts which are equivalent to those transceivers. Good luck in your endeavors!

[–] peregus@lemmy.world 2 points 4 months ago* (last edited 4 months ago)

Thanks a lot! It seems that this from fs.com in the non Aruba compatible brands costs 32€ Thanks again!

Edit: And I've even found the LC/UPC to SC/APC cable!