I am buying a surge protector, and the model I am looking at has RJ11 ports (in and out) for protection. Now I want to ask if its possible to do a RJ11 > RJ45 conversion, so I can protect my Ethernet cable with it. I read someone suggesting TAE plugs, but I am not sure if there is any need of these.

So it is possible to connect my normal Ethernet RJ45 cable with some kind of adapter to a RJ11 slot on my surge protector, and then as showed on the picture, another RJ11 slot on the protector will output a protected line from which I want to convert it back to a RJ45, and if so, how?

Surge Protector

  • Nobody should try to do this, there are lots of cheap enough quality surge protectors that support both. Also, its rude to not accept what is clearly a proper answer to your question! – anders Aug 27 '18 at 12:44

This isn't possible. I mean, technically it is, but not without potentially severe side effects.

If for no other reason, this is not possible, because:

  • RJ11 has 6 wires.
  • RJ45 has 8 wires.

Gigabit and PoE connections use all 8 wires. Even if you could eliminate 2 wires, passing high speed data through a circuit designed for analog phones, is likely to have issues.

To properly protect an ethernet line from surges you need to use a surge protector designed for ethernet. The one you show is designed for a phone line, not ethernet.

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The telephone surge protector likely has just a single pair (two wires). 10 or 100 Mbit Ethernet require two twisted pairs, gigabit four. Additionally, the protector likely doesn't support the high frequencies Ethernet requires (100 MHz as with Cat 5 cabling).

There's no way to do it.

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  • 1
    It's unlikely that the pair is even twisted, just connected to the surge protection devices via untwisted wires. – Ignacio Vazquez-Abrams Feb 10 '18 at 0:06
  • True - I've edit that in, thx. – Zac67 Feb 10 '18 at 10:56

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