BT Landline with Zen ADSL - which order to move services

We have standard BT phone line with a landline number, and Zen ADSL as our broadband.

We wish to retain our broadband with Zen, which is still only FTTC not FTTP, (unless a much better deal arrives on the table!). Presumably we have to re-order a new broadband package with Zen to cover the loss of the BT line - and Zen handles the change over?

Also, we'd like to retain our BT landline number and move it to a cost effective VoIP supplier such as a A&A as we only really use it occasionally, mainly for incoming calls. We'd do it all with Zen, but £7.50 a month is a bit steep for a basic VoIP service.

What's the correct order to do these in, and are there other recommendations?

is the voice part of the line with zen or bt?

BT - landline with PSTN voice telephone
Zen - ADSL only.

Ask Zen what the contract term is on their VoIP product, the easiest thing might be to have them handle your move to SOGEA and the number port from BT, and then for you to port the number back out.

Other options would be to have a new SOGEA service installed on a second line and then porting the phone number which will cancel the ADSL, or living for 2-3 weeks on a 4G/5G service.

Is SOGEA (formerly FTTC) available on your line and you just haven't migrated from an old ADSL service?

If so as you wish to stay with Zen for broadband place an order with them to migrate to SOGEA, this will cease the BT line rental and PSTN service.

Then place an order with A&A for VoIP, this has to be done within 30 days of the number being ceased if you wish to retain it.

You could do it the other way around porting the number first but this would cease the broadband service so you would then have to order a new service to be provisioned on the existing physical line.

You will have gaps in either voice service doing it the first way, or both doing it the second way (as you won't have broadband until provisioned for the VoIP service). Most annoyingly the one-touch migration process completely ignored this scenario, so if you want no break in either service it would be a case of installing a new copper line and SOGEA broadband service, then when active porting the PSTN number which would cease the BT phone line and Zen ADSL.

Assuming that Zen provide a FritzBox if you have some othe ADSL-only router you can configure it to terminate the A&A VoIP connection, the only thing to watch out for is that unless you disable Zen remote management they periodically push settings updates which overwrite the phone settings.

In reply to a post by jpm:

Ask Zen what the contract term is on their VoIP product, the easiest thing might be to have them handle your move to SOGEA and the number port from BT, and then for you to port the number back out.

AFAIK it is 12 months

Thanks all - really useful info.

I think the best route will be the "one-touch migration" SOGEA to Zen, then when it's all ok and contract terms expire, migrate the VoIP away from Zen to something better value. Although 12 months is a bit of a VoIP lock-in, but I've checked and that seems Zen's standard terms.

I'd be tempted to let the BT land-line number expire at the SOGEA migration (not porting it to Zen) and then well within the 30ish days after service ends, hope that someone like A&A could recover the number, but I assume that's a bit risky to lose it? We rarely call from it, but have elderly relatives who always want to call in and don't use mobiles.

We've got a FritzBox already so I assume we'd just keep that and connect the DECT phone to that after migration.

How long does the SOGEA migration normally take? We’ve not been given a cessation date from BT for our current PSTN line, but I want it all sorted long before we might risk a service interruption to the broadband.

In reply to a post by Camtree:

I'd be tempted to let the BT land-line number expire at the SOGEA migration (not porting it to Zen) and then well within the 30ish days after service ends, hope that someone like A&A could recover the number, but I assume that's a bit risky to lose it? We rarely call from it, but have elderly relatives who always want to call in and don't use mobiles.

It should be straightforward but there is always a slight risk if the porting process gets delayed and connot be resolved within the 30 days, e.g. if the gaining provider (A&A in this case) has problems matching records due to name, premises or billing address you give not matching those for the current provider.

We've got a FritzBox already so I assume we'd just keep that and connect the DECT phone to that after migration.

Yes, just plug the DECT base into the phone socket on the FritzBox. If the DECT handsets are compatible you can deregister them from the existing base and register them with the DEC base built in to the FritzBox, you may need to replace the old base with a charging-only one for the one phone.

How long does the SOGEA migration normally take? We’ve not been given a cessation date from BT for our current PSTN line, but I want it all sorted long before we might risk a service interruption to the broadband.

The PSTN switch-off is Jan 2027. From the recent press releases from Openreach if you did nothing by then with your particular setup they would likely cease any broadband service and move the voice to emergency only access.
Whilst same-provider migrations not requiring an engineer visit (to premises, DSLAM cabinet or exchange) can de done in a day I'm not sure if any providers actually use this option so it is usually a couple of weeks, potentially more if an engineer visit is required and they are busy. I'm sure the work queues will lengthen considerably closer to the switchoff date as people who haven't migrated have to.

II have just moved from FTTC to FTTP both with Zen. FTTP with their Full Fibre Max product but they cannot provide telephony with this service. I opened an account with Voipfone ahead of the switch in fibre connection, they provided a temporary number pending the switch and porting our old telephone number across. All worked well with the phone line. So an extra month's telephone service cost but no interruption to service.

My ISP say any orders after 1 Dec 2026 cannot be guaranteed to be migrated in time

Apologies if I'm misunderstanding something, but I think you could simply take out a line with A&A and port your BT classic number directly. If that doesn't automatically terminate your BT service (which I believe it will) then you may have to handle that directly with BT.

I don't see any reason to involve Zen in the phone service migration. Just leave them to provide Internet as at present and/or if/when you can migrate to FTTP. Or switch internet providers if that's worthwhile.

A&A support is very good; you could double-check with them, I suppose.

And, yes, Fritz!Box routers (which I suspect is what you have from Zen) have a Cordless DECT standard base unit onboard so you should be able to pair your DECT handset/s directly to that - as long as you can keep them charged. You can probably carry on using the existing base unit as a charger only if necessary - just ignore the fact it's a DECT base.

Ceasing the PSTN service by porting the number out will also cease any additional services such as ADSL or FTTC, be they from the same supplier (BT in this case) or a third-party (Zen), as the phone number identifies the circuit.