This topic

Multiport ONT blocking new I SP service — speed locked at 100Mbps

wohdivad — Tue, 14 Apr 2026 10:48:31 GMT

Background: Two years ago I wanted to cease my BT phone service but was told it couldn’t be split from broadband. A excellent forum moderator found a workaround — refunding the phone contract cost until renewal. When that contract renewal approached, in March 2026 I moved to Plusnet specifically to drop the phone service that would soon be billed again. That’s when the problems began.

Please treat what I report below as my understanding of the problem only. This has been stitched together from numerous phone calls

I switched from BT to Plusnet in March 2026. My property has a multiport ONT (optical network terminal) with BT on port 1 and Plusnet provisioned on port 2 as confirmed by an Openreach engineer. The problem is a hardware limitation on port 2 of my ONT type — it is physically capped at 100Mbps. My Plusnet package is 145Mbps, which I can never receive on this port.

The fix requires moving the Plusnet service to port 1, but BT’s Digital Voice service was not fully deprovisioned at the Openreach level when they ceased my account. The phone problem yet again perhaps. This blocked Openreach from placing the order to move me to port 1. An Openreach fault (ref: 5-1050430566924) has been open since 17 March. BT’s service has since been confirmed ceased at account level, and port 1 tested dead on 1 April. However, I am still on port 2 for Plusnet and still speed-limited. To compound matters, my old BT number still routes to voicemail that I cannot access — I have no way of knowing what messages I may have missed.

Has anyone had experience getting Openreach to act on a port migration in this situation, or is there any BT community expertise on what’s needed to clear the Digital Voice deprovisioning and get this moving? It’s clearly not simple at all.

Re: Multiport ONT blocking new I SP service — speed locked at 100Mbps

iniltous — Tue, 14 Apr 2026 12:54:23 GMT

Maybe a less important point , but if you no longer have BT ‘Internet’ on port 1 (and hence the belief that you should be able to move PN from port 2 to port 1 of the ONT and that will solve your supposed capped speed from port 2 ) , then what’s the problem with not being able to listen to messages on your what should now be (but isn’t) a ceased answer service , admittedly the BT phone answering service shouldn’t now exist if BT broadband has gone , but presumably you have (or should have )already told those that need to know you no longer have a ‘landline’ phone service so not to use that old number , presumably any messages left are inconsequential, if not , what would these genuine callers that have left messages do if the AVR was ‘this number is not in service’ or a simple NU , number unobtainable tone was delivered .

TBH , the limitation I was aware of was with the old generation multi port ONT was it had an overall bandwidth of 1Gb aggregated over all 4 identical ports so as an example two 500 Mb services would be fine , or 3 x 300Mb services , but not a 900Mb and 500Mb , or any other combination that exceeds 1Gb ….there being no difference between the 4 ports as such , so if your port 1 service is ceased or not ( unless it was 900Mb and still active ) , there is no reason why the limitation you have is because of the ONT , but clearly your BT service has not been completely ceased if DV is still operating at some level (hence the BT answer service that still operates )

Finally as a Plusnet customer , it’s really PN that you need to be chasing as far as their inability to give you the speed you are purchasing , a solution , if you and PN suspect its the multiport ONT as the issue , is to get it swapped out to a single port ONT , the status of the BT service , totally or partially ceased is irrelevant to PN , and from Openreach , it would be no different to you having two separate ONT’s with one removed from the mains power .

Openreach have nothing to do with DV , there is no difference at all from Openreach perspective to an ISP customer with IP telephony either a proprietary version delivered by the ISP router or an independent VoIP service via an ATA , and an ISP broadband only customer, if port 1 is effectively dead in that a router doesn’t connect to the ISP network anymore (the PON is still up regardless of that ) then BT have no further ‘hold’ on the port even if DV hasn’t been deleted in BT DV systems , in effect OR should have the port ready for another ISP , I suspect PN don’t ‘know’ how to enable the shift of their service from port 2 to port 1 rather than port 1 still having a partial BT service on it , so in that case basically providing PN on its own single port ONT is relatively straightforward, no different to if the ONT went faulty, Openreach simply assign the single port ONT serial number against your PN service.

Re: Multiport ONT blocking new I SP service — speed locked at 100Mbps

wohdivad — Tue, 14 Apr 2026 14:02:57 GMT

Thank you iniltous for that very comprehensive reply. As I said any 'knowledge' I have is very much second hand.

As far as the voicemail is concerned what you say is largely true. My issue, apart from the fact it is a personal greeting message (ie my voice), is that I am in my seventies and am waiting for specialist appointments with the NHS. Despite my efforts to delete this landline number there is no central NHS database so some departments may call on the landline number and leave an important message. Non response from me may result in my deletion from the horrendously long waiting list I'm on. Too much detail but that's my concern.

Perhaps worth reiterating is PN's insistence that BT still have an unresolved fault with Openreach on this and until that is resolved PN cannot open another. I've no idea what this is.

Thanks again. I will continue my battle with PN which largely involves being pushed from pillar to post.