This topic

Smart Hub 2 connections

delta_wing — Wed, 08 Oct 2025 14:31:34 GMT

Hi guys.

Currently on FTTC.
Having FTTP in a weeks time.

Cat 5e cable (white) goes from the Openreach MK2 wall box to the box in the office shown in picture bt2.
Then a cable (black) out of this to the back of HH5.
This plugs into HH5 as shown in picture bt1.
Will this same cable just plug into the new SH2?
Or do I need an adapter?

Many thanks.

Re: Smart Hub 2 connections

delta_wing — Wed, 08 Oct 2025 14:43:02 GMT

Sorry should have said the cable in question is the one on the left of the HH5 not the ethernet (yellow end).

Re: Smart Hub 2 connections

licquorice — Wed, 08 Oct 2025 15:03:40 GMT

No, the connection between the ONT (optical modem) and the Smart Hub 2 is Ethernet.

Your existing wiring is no longer used.

Re: Smart Hub 2 connections

delta_wing — Wed, 08 Oct 2025 15:24:16 GMT

Thought so!

Am I correct in saying I can cut the end of the Cat5e cable and use a tool that crimps an ethernet plug on.

Saves running a new cable through the loft!

This can then be plugged into the SH2?

Re: Smart Hub 2 connections

WSH — Wed, 08 Oct 2025 15:36:35 GMT

You need a Cat 5e cable from the ONT to the Smart Hub 2. (The HH5 is obsolete, so they will send a replacement). There would be no point in cutting the plug off the Cat 5e cable as you need it.

(I suspect what you are referring to is the cable currently plugged into the grey RJ11 port. That is not Cat 5e and will not work with the ONT).

Edit: To clarify a bit further...

FTTC is Master socket….RJ11 cable….RJ11 port on the HH5 then ethernet from one of the LAN ports to the rest of your network.

FTTP is ONT…..Cat 5e…..WAN port of the Smart Hub 2 then ethernet from one of the LAN ports to the rest of your network.

RJ11 cable is four wire, Cat 5e is eight wire, so the RJ11 cable will not work with the ONT.

Re: Smart Hub 2 connections

licquorice — Wed, 08 Oct 2025 15:35:28 GMT

You are also assuming that the location of the ONT will be tha same as your current master socket location. That is not necessarily the case.

Re: Smart Hub 2 connections

licquorice — Wed, 08 Oct 2025 15:39:02 GMT

@WSH I suspect the OP may have used Cat5e cable between the master socket and the socket shown in the screenshot and only used 1 pair.

Re: Smart Hub 2 connections

WSH — Wed, 08 Oct 2025 15:55:24 GMT

Yes, I thought that. The cable looked like flat RJ11 to me but it's very difficult to tell in the photo.

Re: Smart Hub 2 connections

delta_wing — Wed, 08 Oct 2025 16:00:40 GMT

The current Cat 5e cable runs from the Openreach box (new picture) some 10 metres through the loft to the into the white box as shown above.
Then to the HH5.

The ONT box will be next to the Openreach one so this end of the Cat 5e will plug straight into the new ONT?

The other end of the Cat 5e is at the office end.
Can I not crimp on an ethernet plug which will then plug into the new SH2?

If not we will have to run a new Cat 5e (or Cat 6 or more) from the ONT to the SH2.

Re: Smart Hub 2 connections

licquorice — Wed, 08 Oct 2025 16:11:11 GMT

The plug shown is an RJ11, not an RJ45.

However, the cable is in situ, you simply need to crimp all 8 wires in RJ45 plugs at each end.

Re: Smart Hub 2 connections

delta_wing — Wed, 08 Oct 2025 17:03:09 GMT

Thanks for the reply.

Just out of "technical interest" why does the Cat cable for the ONT/SH2 need 8 connectors?

Re: Smart Hub 2 connections

licquorice — Wed, 08 Oct 2025 17:05:54 GMT

Because it is a 1Gb link which requires 8 wires.