Home phone service upgrade (DV?) - impact on other services using landline

[grainywand]

We’ve just (4/12/25) received a BT letter indicating that our home phone service will soon be upgraded - to Digital Voice (DV), presumably, though, neither the letter, nor the accompanying leaflet, explicitly say so?? The letter goes on to say that they’ll be in touch to confirm the upgrade date (which we’ve not had yet, as we’ve only had the letter a week), and that, on the upgrade day itself, all being well, the engineer will then carry out the work remotely at the telephone exchange.

My concern is that this implies that the BT landline is only used for our BT home phone service, but the situation is more complicated than that, and the upgrade will surely impact the other 2 services that use our landline?? - namely …

1. Our 3rd party (Plusnet) FTTC Broadband service - which nevertheless uses the BT landline (I understand), and BT should surely therefore know about it.
2. Our Monitored Burglar Alarm - also connected to the phone line, to allow it to communicate with the central alarm monitoring station. Note that it only communicates alarm status changes occasionally/briefly using the phone line (eg. alarm set, alarm tripped, etc), and it uses relatively old technology (Digicom, I think?). I obviously don’t expect BT to know about this alarm connection, but it will surely still be affected by the phone service upgrade?

I knew that the BT home phone service upgrade was coming (it’s been on the horizon for ages), but when this formal/individual BT letter came, I expected it to give us the opportunity to raise any issues (like those above), but there’s no obvious way to do so. I don’t know how much advance notice of the upgrade date we’ll get, but I wanted to get ahead of the game and raise these issues now. The BT letter says to call 0330 1234 150 for more info, but that’s just the generic BT contact no., which would no doubt just be an Indian call centre, or similar, who wouldn’t be able to help with anything non-standard like this. Hence, this post on the BT Community, in the first instance.

I’m really just trying to understand the impact of this upgrade on all 3 of our services that use the BT landline, and the possible options, going forward - eg. we might consider getting rid of the BT home phone service (as we don’t use it much now and could just use our mobile phones), change the alarm system’s mode of communication (eg. switch to a mobile-based comms module), and upgrade to full fibre broadband (FTTP) (probably, still Plusnet - see Note 1 below).

In any case, whatever we do will obviously need to be well-coordinated across all parties, to avoid major disruption to our phone/broadband/alarm services (being so interdependent).

(Note 1: our preference is to keep our Plusnet Broadband because we have ISP-based email addresses, which are linked to literally hundreds of internet accounts/services/communications, so it would be a major undertaking to change those email addresses!)

I hope the above makes sense - any help or advice with this would be hugely appreciated, as we’re not sure how else to raise these issues, or indeed, what to do about our 3 services.

[iniltous · Accepted solution]

Presumably you have SMPF (shared metallic path facility ) if you pay BT and Plusnet separately for telephony (BT) and broadband (PN) , you are one of very few still on this what is now a legacy arrangement , it’s unnecessarily expensive, you probably are paying at least £20 a month more that necessary if either BT or Plusnet provided both services and presumably have been paying this for many years (SMPF has been something of a niche product for a decade and not sold to new customers for quite a few years )

BT recently introduced something called a  pre digital phone line , that can be used to get ordinary BT phone only customers off PSTN telephony but it’s not applicable in your case as you have broadband from PN , and PDPL doesn’t support what you have .

You need to (and it’s something you could  have done at any time in the last few years and saved yourself  probably upwards of £500 ) , is to decide who to use for both services (if you want to keep both that is ) , but  given Plusnet are not offering telephony to new customers anymore and migrating existing phone customers to BT or EE if they want to keep that facility, you won’t be able to chose PN anyway , that is unless you drop the phone service anyway .

As far as your alarm , that’s really you alarm providers problem , you should be speaking to them about that .

[grainywand]

Hi @iniltous - many thanks for the quick response, that’s really helped to clarify the way forward!

I’d never heard of SMPF before, but we must have that as we definitely still have copper wire for the last section of the BT line to the property, and that must be shared by BT (phone) and Plusnet (FTTC Broadband), as we do pay them separately for those services.

You’re right that it’s a very unusual/legacy situation that we’re in! - it really just reflects the history of how things developed. We’ve lived here for over 25 years, and when we moved in, in 1999, we only had a BT landline (like many people), in the days when home internet wasn’t commonplace. Later, when dial-up internet became widely available, we signed up with Madasafish (an old ISP, subsequently taken over by Plusnet), as I don’t think it was available from BT, then (though I could be wrong about that, as it’s a long time ago!) … and we then just progressively upgraded our internet connection, through Plusnet, to Broadband Max, and then FTTC Fibre Broadband, when they became available, as it was easiest to stick with them.

You’re also right that we need to talk to our alarm company (they did warn us that the BT home phone upgrade was now imminent and would have an impact), and I think we need to start by ‘divorcing’ our alarm system from the phone line, asap (probably change to mobile-based comms with the monitoring centre, as already mentioned). For info, we do occasionally get interference from the phone, causing the broadband to drop out, briefly, and I think that’s actually down to an intermittent issue with the phone line ‘spur’ connection to the alarm, rather than a problem with the SMPF (which is obviously designed to work with phone/broadband, together).

I think we’ll then ditch the phone landline (the alarm is really the only requirement for it, so if that goes), and upgrade to Plusnet* full fibre (FTTP) (*due to the emails issue already mentioned).

If you don’t mind me ‘picking your brains’ a bit more to complete the picture, just a few more quick questions/ clarifications for you …

1. If we do upgrade to Plusnet Full Fibre (FTTP) will that ‘automatically’ result in the BT landline/associated contract being turned off/terminated? Or, will we need to contact BT, too?
2. Leaving the alarm connection to one side (as I know that’ll be affected), as a matter of interest, would our existing phone/FTTC Broadband even work, after the BT upgrade to DV, with our current setup (SPMF)? Or, would it ‘expect’ to see a BT Router on the end, with our existing DECT phone connected to that? … rather than our Plusnet router, and the separate phone connection to the BT master socket on the wall? It’s not clear from the BT letter/leaflet we received whether the DV upgrade includes/implies replacement of the last section of copper wire to the property, with fibre?
3. Have you any idea how much time we’re likely to have before the BT home phone upgrade actually happens? (given that we’ve only just received the BT initial ‘warning’ letter about it). It obviously won’t be a quick process to get, both, the alarm system modified, and, the Plusnet FTTP upgrade done, especially around Xmas! … though BT probably won’t be doing much DV phone service upgrading around Xmas, either!!

Huge thanks again in anticipation of your responses to these few additional questions!

I’m really pleased that, with your help, the plan for the way forward is now much clearer.

[iniltous]

1.If you become a FTTP customer with Plusnet , the status of your BT telephone service can’t be predicted with any certainty, what’s more if Plusnet treat your application for FTTP as totally separate to your existing SMPF FTTC service you may conceivably have FTTC and FTTP simultaneously , unless you advise BT yourself to cease your telephone service , then obviously you are dependent on what PN do with your broadband and notification towards BT …historically telephony can exist without broadband but broadband (on legacy SMPF) can’t exist without telephony from someone .

2.Although you have received some advanced notification, your situation as a SMPF isn’t really clear , BT can’t arbitrarily remove Plusnet , Plusnet can’t arbitrarily remove BT , but both services cannot remain as they are , you will need to decide , if you leave it , presumably one or the other (or possibly both ) will remove their service.

3.The absolute last date for PSTN retirement is Jan 2027 , your BT telephone service will either change to DV (if you remain a BT customer ditching Plusnet ) or be removed by this date , in which case you won’t be a BT customer , your relationship with PN would need to be discussed with them .
TBH it’s seems clear your preference is to join PN on FTTP , personally I’d arrange that migration, if you get a notification from BT that your telephone will be removed by this action , great that’s what you want , if you don’t get a notification from BT , independently of PN , you ask BT to cease your telephone service , potentially after the FTTP is installed, that way no break in broadband service is likely

[grainywand]

Many thanks again for the quick responses, @iniltous, that’s all really helpful!🙏👍😁
I’ll just get on with it now, as soon as possible, allowing for the Xmas/NY break …