this post was submitted on 08 Aug 2025
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Here’s a question that I can’t seem to find more info on the internet on, so I’m turning to Lemmy. Does anyone have a better understanding of the specifications around an ONT. I know it basically converts the incoming fiber (usually single mode single fiber) to an RJ45 jack for copper runs but that’s the part I’m curious about:

  • does it convert it to use standard Ethernet frames or is it a proprietary protocol?
  • if Ethernet, is the port speed 1G, 10G, etc or based on the hardware?
  • if it’s a proprietary protocol, what does it use?

I recently got a new router and noticed it’s capable of 5Gbps on one port, but that got me thinking about the ONT and if I were to upgrade my service would i also need the ONT replaced too?

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[–] Coelacanthus@infosec.pub 1 points 3 days ago

It "converts" from and to Ethernet frames, of course. There is not actual L2 difference between PON network and normal fiber ethernet network. In simplified description, it just replace active switch with passive optical splitter.

Yes. Like fiber ethernet, differnet speed need different ONT. But noteworthy, there are some different standards for the same speed level, they are incompatible. For example, EPON and GPON, they are both for 1GbE but incompatible.

[–] Intheflsun@lemmy.world 2 points 1 week ago

I'm in the US, had Verizon at the time. Switched from 750Mb to 1.5Gb and they had to swap in a new ONT because the switch side in the old one capped at 1gig. New ONT was up to 5. I have no idea where you'd check the specs for it. Mine is mounted and the info sticker is probably on the side against the wall.

[–] who@feddit.org 2 points 1 week ago* (last edited 1 week ago)

The ones I've seen use standard Ethernet frames.

Supported port speeds would depend on each ONT's design. If you upgrade your service to a speed that your current ONT can't handle, then you would need a different ONT, of course.

[–] ReticulatedPasta@lemmy.world 1 points 1 week ago

Most I've worked with are not vendor-specific and use Ethernet frames. If you know the specs of your ONT, you can even buy an SFP that can connect directly to your router in place of the ISPs ONT. https://www.fs.com/c/xgspon-xgpon-combo-4897