topic Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number in Full Fibre

Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 13:54:46 GMT

Hi, I'll try to be quick!

Situation: I've ADSL via Plusnet + BT Landline number. Will lose "soon" due to switchoff. I should be able to get FTTP.

What I want: Fibre via Plusnet / BT number kept with VOIP provider.

Question: Order of things and concurrency.

Googling I've read a number of tales of woe about losing numbers and so on when losing the landline on the plusnet forum when they get a fibre upgrade but I just realised these people seem to have had their phone with plusnet NOT BT.

My ASSUMPTION was that when fibre is installed, BT/Openreach DISCONNECT the landline. Basically SWAP the service across while they are there. Google "AI" results have **explicitly said that is exactly what happens** when I search (a number of times!) but it's often wrong of course.

I've also read the simple way to do this is to just get the fibre installed THEN move the BT number to VOIP. Which sounds better but contradicts the above.

So Question. Is it quite possible (in fact better) to get fibre installed and just tell BT nothing, so that for a while I'll just have fibre AND my landline number? Then move my BT to VOIP once dust settles? Basically: Will a fibre install NOT affect my landline, other than disabling ADSL?

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

corringham — Wed, 04 Mar 2026 14:23:37 GMT

First thing to check is whether you can get FTTP or SOGEA (FTTC). If FTTP is available then you should be able to get that installed and keep your ADSL + phone line active - once FTTP is active then move your phone number to the VoIP provider of your choice, that will terminate the phone and hence ADSL. If only SOGEA is available then move your broadband to that, which will terminate your phone line too, and you will then have 30 days to transfer the number to VoIP.

If neither FTTP or SOGEA are available then you'll need to investigate 4G as very few ISPs offer SoADSL.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 14:37:08 GMT

I'm fairly sure I can get FFTP, there are these boxes around installed a couple of years ago that look like a black cows udder.

Which is quite the metaphor, wonder if I invented it, Freud might have a field day with me

They run into neighbours homes and I know a neighbour has an ONT box from one.

OK well if I can keep both that's less stress. I've read quite a few people can have issues (not with plusnet) as well but I think it's often the case they are switching landline + fibre out/across from same provider, which I am NOT doing. BT forums have a number of people complaining about lost numbers, looks like as I can do it in two steps I should be OK (touch wood).

I rarely use my landline but it's handy for people to call me in Emergency if my mobile is off etc.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 14:42:39 GMT

@Kwak

Use the following to check that Full Fibre is available. You're looking for WBC FTTP in the left column. If it's there what does it say to the right - One stage or KCI2?

Below the results window will be a narrative on the FTTP install - specifcally if any problems are expected.

https://www.broadbandchecker.btwholesale.com/#/ADSL

For FTTP a new cable is run to your property. You lose the landline on the day of install as FF takes over your service. You then have 30 days to port the number to the VOIP provider of your choice. Note you cannot do this before FF is installed and working. You might have a few days downtime on the phone,.

If you try to move before the FF install this could cause the cancellation of your phone line and hance your broadband service which in turn can lead to the FF being cancelled.

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

corringham — Wed, 04 Mar 2026 15:10:52 GMT

@bmc wrote:

You lose the landline on the day of install as FF takes over your service.

That doesn't need to happen if FTTP is ordered as an additional new service rather than as a regrade of the ADSL.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 15:03:10 GMT

My result says

WBC FTTP	Upto 1000	Upto 220	--	Available	1 Stage

You see this is what's worrying, I've 2 "seasoned champion"s responding to my post and you are totally contradicting each other

BT had written to me with a letter about losing the service as I've landline/adsl split, trying to get me to move to BT.

To me, the more I think about it, if fibre is separate service I just "detach" the ISP part and convert it to fibre, so why does the landline need disconnected then, it's an additional service to the landline .. sigh..

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

corringham — Wed, 04 Mar 2026 15:10:10 GMT

The problem with ADSL is that it is always associated with a phone line - even if the ADSL and phone service are provided by different companies. Cancelling one will cancel the other - and as BT are closing their PSTN phone service down and moving customers to Digital Voice that will shut down your Plusnet ADSL. Worse, since VoIP needs broadband, BT will sell you their FTTP with Digital Voice.

If you were to transfer your Plusnet ADSL to Plusnet FTTP then you would lose your phone line, as that would go away when ADSL goes.

However, if you don't transfer the ADSL but get a new additional FTTP broadband connection then both can coexist until you cancel either the phone or ADSL.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 15:29:19 GMT

@Kwak

We're not contradicting each other per say. I missed the part where you said you were on a BT landline and PN ADSL broadband. This complicates matters slightly.

BT Retail have been transferring their landline customers onto their Digital Voice service by area to prepare for the closure of PSTN in January 2027. Hence the letter from them.

My advice still holds good as such. Order FF from PN and when it's installed your BT landline will be terminated. However, you may be due early termination charges from BT.

The landline is going this year, one way or another so now would be as good a time to say bye bye. However it is possible to keep it for the time being if you're willing to pay. You order FF from PN but make it clear it's a new installation and not an upgrade.

This way the old service continues for a short time until BT move it to digital but you would be liable for ETC's from PN when the ADSL service is terminated and you lose any PN add ons like email.

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

HPsauce — Wed, 04 Mar 2026 15:32:45 GMT

I did something similar a while back, you probably need to phone in and VERY CAREFULLY explain that you want an additional service as otherwise you could end up compromised.

(In my case I was on BT landline with PlusNet ADSL and installed a NEW SOGEA FTTC line alongside as there's no FTTP here for a while)

Once my new line was up and running I cancelled the old ADSL, that didn't affect the BT phone line.

Shortly after I transferred my phone number to A&A which also terminated the BT landline.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 15:35:03 GMT

"The problem with ADSL is that it is always associated with a phone line - even if the ADSL and phone service are provided by different companies. Cancelling one will cancel the other"

You see this to me doesn't make sense. If you've a BT phone service, why would cancelling ADSL cancel the phone service?

In post #2 you said

"If FTTP is available then you should be able to get that installed and keep your ADSL + phone line active - once FTTP is active then move your phone number to the VoIP provider of your choice, that will terminate the phone and hence ADSL"

Ahh wait it I needed to re-read that carefully and what you just said. You are suggesting i keep ADSL and Fibre concurrently.

Do you mean I then have TWO services with one plusnet account? ADSL broadband + fibre? So it's not an fibre upgrade, it's a totally new additional product purchase? That seems a bit mad and I fear something unforeseen might happen

In the portal there is just "contract details" and "current package" not "Your contractS" and "Your packageS" etc.. worrying:

I've a static IP, how could that work, it couldn't. I've also a plusnet email address and webspace, I don't want that lost either!

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 15:35:39 GMT

@Kwak

The Checker does indeed show you can get Full Fibre.

The boxes installed on the poles are called Connectorized Black Terminals (CBT). A fibre cable is plugged into this and then run to a property. At the property it connects to an external box called a Customer Splice Point (CSP). It then gets brought into the property to the Optical Network Terminator (ONT). This needs a power source. The router conencts via an ethernet cable so can go anywhere you're happy to run said cable.

You said you don't use the phone much. Have a look at A&A for VOIP - they are cheap if you don't make many outgoing calls. Note that VOIP does not work during power cuts unless backup is in place.

https://www.aa.net.uk/voice-and-mobile/voip-information/

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 15:38:03 GMT

"This way the old service continues for a short time until BT move it to digital but you would be liable for ETC's from PN when the ADSL service is terminated and you lose any PN add ons like email."

This is what I'm worried about. It's all pretty confusing (though I realise this is apparently BT's fault for forcing it).

There is obviously no physical reason they couldn't just turn off the ADSL and keep the land line working for a few months.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 15:39:48 GMT

@Kwak

Cancelling the phone line does cancel the ADSL service. However, cancelling the ADSL service does not cancel the phone line. As I understand things an upgrade to Full Fibre does trigger a BT phone line cancellation but it's something to keep and eye on.

Your Static IP and add ons from PN should be unaffected by an upgrade.

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 15:56:52 GMT

I'm re-reading post 2:

"of your choice, that will terminate the phone and hence ADSL. If only SOGEA is available then move your broadband to that, which will terminate your phone line too, and you will then have 30 days to transfer the number to VoIP."

I'm not clear here. If I do the simple ADSL to FTTP upgrade, and this terminates the phone line, do I still get the 30 days?

The way this sentence reads it MIGHT be I only get the 30 days if it's SOGEA.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 16:02:50 GMT

"Your Static IP and add ons from PN should be unaffected by an upgrade."

Ok thanks, but that's the upgrade. You said .. "This way the old service continues for a short time until BT move it to digital but you would be liable for ETC's from PN when the ADSL service is terminated and you lose any PN add ons like email."

So I've 2 options then?

1. Upgrade to FTTP, lose landline immediately, THEN contact VOIP guys within 30 days to try and get number (but I've read horror stories), lose phone number for days/weeks.

2. Keep ADSL, get a second package with FTTP, lose plusnet services, contact VOIP, transfer landine number, cancel ADSL, get hit (maybe) with some ETC cost from PN as Ive.. what .. a new parallel PN account by sounds of things. Not contract WITHIN the existing account.

Is this correct?

Sigh, it shouldn't be this complicated

This must be a nightmare for people who rely on a landline etc

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 16:32:38 GMT

@Kwak

You have 30 days to port the number from when it's ceased. You do it asap once FF is installed just in case of a problem which gives you time to try and get things sorted. I suspect most of the horror stories are from the past - I've not seen anything on this Forum recently.

1) Correct - you lose the landline but it's usually for a few days.

2) A second account from PN does indeed lose all your add ons plus you have to pay for it.

If you were to choose A&A for VOIP you can set up an account beforehand with a generic number. This gives you the chance to ensure your phone works with VOIP. When FF is installed you then port in your own number and once this has happened cancel the generic number,. Cost a bit more but it gives you peace of mind that your phone still works on VOIP.

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

RobPN — Wed, 04 Mar 2026 16:35:51 GMT

@Kwak

You're overthinking this and making things far harder for yourself than it actually is.

You want to keep your fixed IP address and possibly other things associated with your present PN ADSL account, so your only option is to upgrade your PN ADSL account to FTTP, which in turn will cease your landline. You then port your landline number to VoIP using someone such as A&A who have a reliable porting reputation.

BT are very unlikely to impose ETCs.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

Kwak — Wed, 04 Mar 2026 16:45:40 GMT

Ok thanks and thanks to everone, @bmc and @corringham, I'm glad I asked as this needed clarified.

It's certainly not I think intuitive as to how it works, specifically ADSL being pulled pulls a landline number.

Looks like fibre then dealing with voip is the way.

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

bmc — Wed, 04 Mar 2026 16:57:37 GMT

@Kwak

Happy to be of help.

Do let us know how it goes.

Brian

Re: Query about fibre upgrade and concurrent landline/fibre + keeping BT phone number

MisterW — Wed, 04 Mar 2026 17:03:20 GMT

@Kwak

It's certainly not I think intuitive as to how it works, specifically ADSL being pulled pulls a landline number.

I'm not sure that simply canceling your ADSL service with Plusnet would cancel the BT line. The other way i.e canceling the BT line WILL cancel the Plusnet ADSL. That doesnt help you though, since canceling will close your Plusnet account and terminate all your PLusnet services i.e static IP, email etc

However, upgrading the Plusnet ADSL to FTTP (or SoGEA) WILL cancel the BT phone line. The reason is that Plusnet will place a 'change of ownership cease' on the line as part of the upgrade process.