» ISP News » 
Sponsored Links

BT Expands Pilot of UK Digital Voice Service to More Customers

Tuesday, May 30th, 2023 (4:38 pm) - Score 4,832

Broadband ISP BT will this week expand the rollout of their Voice-over-Internet-Protocol (VoIP) based Digital Voice product, which was only recently restarted with a smaller group of customers after a long pause (here), to include “all full fibre and a smaller group of broadband customers yet to switch to Digital Voice.”

In case anybody has forgotten. The Digital Voice product was designed to replace BT’s old analogue phone service, which will cease to function once the Public Switched Telephone Network (PSTN) is completely withdrawn by December 2025. After that point, all future phone services, whether delivered via copper (ADSL, FTTC, G.fast) or Fibre-to-the-Premises (FTTP) lines, will become IP (internet) based and require broadband to function.

NOTE: The move to IP based phone services is NOT limited to BT. The same challenges are industry-wide and affect all providers of phone services.

However, the initial rollout of Digital Voice suffered a few problems, which are common to most IP based phone services. The difference being that, for many UK people, this will be their first experience of such issues. For example, the setup is different as you have to plug your handset into a broadband router or ATA (analogue) adapter instead of the wall socket (more details). On top of that, a lot of old systems designed for the analogue service (e.g. home alarms, remote medical monitoring etc.) don’t function with IP based lines and may need an upgrade.

Furthermore, the loudest gripes came from those – particularly vulnerable and landline-only phone users – who quickly discovered that IP based phone services tend to fail in a power cut as they can’t be remotely powered. In order to resolve this, ISPs need to deploy Battery Backup Solutions for your handset, router and ONT (the latter is only relevant if you have FTTP), but these will only last for an hour or a little more. Hard luck if you need to call 999 in an area with no mobile signal, during a protracted power outage.

As a result of all that, and a fair bit of negative publicity in major newspapers, BT paused their Digital Voice rollout last year to update their approach and take more account of the various concerns (more details). A pilot of the new upgrade process only began again last month, and they’ve so far upgraded 2 million customers, which leaves another 7-8 million left to do across the UK. But now the next phase is due to begin.

Lucy Baker MBE, All-IP Director, BT Consumer, said:

“Customer feedback from these trials has also been really positive, which has given us confidence to now extend these trials further to a wider group of customers across the country who are ready to make the switch. From this week, we will be contacting all full fibre and a smaller group of broadband customers yet to switch to Digital Voice.

As before, we won’t be proactively switching customers who fall under any of the below criteria, where we have this information available:

Customers with a healthcare pendant
Customers who are over 70
Customers who only use landlines
Customers with no mobile signal
Customers who have disclosed any additional needs

These customers will be delayed from switching as work continues with stakeholder groups to build confidence in the new solutions we have, help to shape the solutions we’re developing and help them to better understand the support available to make the move.”

After this, the next phase will begin during this summer, when customers will be encouraged to make the switch to Digital Voice on a region-by-region basis. The first three regions will be the East Midlands, Yorkshire & Humberside, and Northern Ireland. In addition, customers who are ready and keen to make the switch to Digital Voice, can also contact BT at any time, as many have continued to do.

Customers in these regions will be contacted at least four weeks before being upgraded, to help ensure they’re ready to make the switch. The regional approach will be supported by general awareness communications, and advertising campaigns, delivered across local and regional media to explain to customers the simple steps required to make the move to Digital Voice. BT will also be present on high streets across the country and at local town hall drop-ins to help explain the change.

However, while BT may currently be taking most of the flak for related problems, the reality is that all broadband and phone providers that operate older analogue phone services can only do so much on this front to cover for power outages and other issues, while at the same time needing to keep the transition both affordable and practical.

The reality is that VoIP solutions work a bit differently, and we’ll all have to adapt to that (other countries have faced similar challenges) because no amount of criticism will reverse the move away from older copper and analogue phone services. BT has at least done a lot more to tackle the concerns than others.

Like it or not, the old analogue voice service has long been destined for the rubbish bin of history, and indeed very few people today make much use of their landline phone. Most home users now prefer mobile, VoIP and internet messaging, while home phone services have become more of an optional add-on.

BT’s General Digital Voice Improvements

➤ Hybrid phones that can switch to a mobile network and have a built-in battery.

➤ Customers can now nominate a family member, friend or carer who will receive all the information about switching on their behalf.

➤ Existing customers with additional needs such as health pendants, or those without mobile coverage at home, will be able to take advantage of free additional support. These options range from free battery back-up units to engineer supported installations or hybrid landline phones.

➤ BT are also continuing to invest in the Shared Rural Network, improving 4G mobile coverage in more than 900 areas across the UK by the end of 2023.

➤ And they’re continuing to work with healthcare pendant and burglar alarm providers to ensure the most vulnerable customers continue to get the service they need.

Share with Twitter
Share with Linkedin
Share with Facebook
Share with Reddit
Share with Pinterest
Tags: , , , , ,
By Mark Jackson
Mark is a professional technology writer, IT consultant and computer engineer from Dorset (England), he also founded ISPreview in 1999 and enjoys analysing the latest telecoms and broadband developments. Find me on X (Twitter), Mastodon, Facebook and .
Search ISP News
Search ISP Listings
Search ISP Reviews
50 Responses
  1. Avatar photo Ben says:

    Switching to the mobile network in the event of an outage is all a bit academic when the mobile network also has poor resiliency: https://www.standard.co.uk/tech/power-cuts-sussex-london-mobile-phones-burgess-hill-b1067548.html

    1. Avatar photo Niall says:

      the likelihood of both the fixed line broadband + mobile network going down at the same time very slim. How much downtime have you experienced on your mobile phone network in your lifetime?

    2. Avatar photo Bubbles says:

      When the power goes out in a rural area, like just outside bradford ( 🙂 ) and you have no access to fixed line at your house and thew local 1 mast per operator per village goes offline because it doesn’t have a battery either

      it then becomes an issue.

    3. Avatar photo ROBERT NORRIS says:

      I found the phone useless battery life poor had to keep switching to another phone,would cut caller off and buttons so close together just had to drop and phone cut off ,heavy and bulky put old phone back much better

    4. Avatar photo JR says:

      In 2021, Storm Arwen hit the North East of Scotland, and many communities had power outages for over 7 days. A wide power outage also meant the telecoms infrastructure was running on generators and back-up power, so alot of residents also faced a comms blackout for the same amount of time. The powered analogue phoneline was a literal life line for many rural residents. A one-hour resilience solution doesn’t provide people with alot of optimism.

    5. Avatar photo Ben says:

      @Niall read the article I shared — 2 outages in March 2023, each lasting over 3 hours. The mobile masts gave up within minutes.

  2. Avatar photo Obi says:

    Wonder how much bandwidth will be used. Being part of the minority with ADSL, uploads are a pitiful 1mbps.

    1. Avatar photo Rich says:

      Around 100-200 Kbps I believe.

    2. Avatar photo Obi says:

      @Rich Not too bad

    3. Avatar photo 125us says:

      Less than 100kbps for a-law PCM using RTP and SIP. A more modern codec is more efficient. Mobile networks can drop to as low as 8kbps and still achieve good quality.

  3. Avatar photo joshe says:

    Vodafone forced my grandmother who is 81 to move to VOIP landline, was that supposed to happen? It’s not a problem anyway as I’ve told her to use her phone instead as it doesn’t cost any money and the landline works perfectly, but she is still vulnerable.

  4. Avatar photo Gavin says:

    My family and I are in those vulnerable categories, and have BT as the ISP, yet never got offered any extra help with battery backup.

    Also I was told I could still use my regular old phone line and wouldn’t be forced to digital. But within 24 hours of DV and my FTTP going live, the regular phone line went dead. I was told I had to order phone line with FTTP otherwise I’d lose my phone number.

    So they are forcing vulnerable people on to DV with no backup.

  5. Avatar photo James says:

    What about making Digital Voice work with those of us who use 3rd party routers?

    1. Avatar photo tech3475 says:

      This is something I’d love to see from BT and others, so far the only ISP I know of who will provide SIP details is Zen.

      Giganet is supposed to be launching something relatively low cost but there’s no timeframe and I don’t know what their setup will be.

      Otherwise going third party for VOIP seems to be the only option and that can quickly become relatively expensive if you want inclusive calls to landline and mobile.

    2. Avatar photo Ivor says:

      what’s the business case for doing so? It adds a lot of additional complexity and the number of people who must use their own router and still want a landline service is not that large.

      IIRC Ofcom treats DV as a landline service, not a VoIP one, even if that is how it is delivered. That means there’s more responsibility on BT to provide a usable service, and they’ve decided that means they need to control it from end to end. That means there won’t be any complaints because it won’t work with a 20 year old ATA or some big name IP phone that was never fully SIP compliant as it was only ever intended to work with that vendor’s IP PBX platform, etc.

      If you must have BT phone and broadband, you could always move to BT Business where they do supply a separate device. Might cost more though.

  6. Avatar photo BuckleZ says:

    Let us use our own routers and still use DV.

    I pay for a line I can’t use, (I thought by now they’d have an alternative for own hardware.

  7. Avatar photo Just a thought says:

    We have directives that state mobile phones must use a common charging interface (now USB-C) to increase compatibility and reduce electronic waste

    Maybe OFCOM should dictate that OLT, router and ATAs should conform to a similar standard. In that way it would be possible for 3rd party battery backup systems to be placed inline with each of the devices, powered by one PSU and containing one larger battery giving backup to all vital components without the endless need for more sockets and individual BBUs.

    1. Avatar photo Tom C says:

      These devices already exist. And they are relatively cheap. There’s nothing special about the power supplies that power routers. Usually just a 12v power plug that are inter-changeable as long as they provide enough power.

    2. Avatar photo Tech3475 says:

      I’m curious now as to the potential power efficiency between something like this vs just using an off the shelf UPS with a reasonably sized battery.

    3. Avatar photo XGS Is On says:

      The UK isn’t important or large enough a market for our regulator to demand vendors from around the world conform to a standard we set.

    4. Avatar photo Ivor says:

      I suppose the idea is that USB-C would mean we could all use the battery banks we have lying around the house, rather than buying yet another device (Eaton makes one that looks remarkably like a typical portable battery bank, but designed for powering home routers). Probably more efficient than the AC > DC > AC (+ final DC) conversion that most UPSes do, though I gather the BT UPS is DC output.

      You can sort of do this already, though it means either buying a battery bank that actually provides a 12V output (it is not part of the USB-C spec so many don’t) or using a regulator to bring it up/down, which is what I did.

      I don’t accept the argument that the UK is too small a market. The major ISPs already have devices custom made to their requirements, and the likes of Openreach don’t have to use an entirely off the shelf device either.

    5. Avatar photo XGS Is On says:

      Vendors customise CPE for ISPs all the time. The customisation more like branding with minor case alterations but it’s done. They also pay for it. Very different story from demanding all vendors adhere to standards of interoperability in some way that don’t apply in the rest of the world because it’s us.

      The kit that Openreach provide is, besides the branding and casing, off the shelf.


      It’s not a bad idea I just doubt that the UK has the regulatory clout to force suppliers to change their products.

    6. Avatar photo Sam B says:

      @XGS is On

      “The UK isn’t important or large enough a market for our regulator to demand vendors from around the world conform to a standard we set.”

      That’s an odd statement considering all landline phones sold in the UK are fitted with the BS6312 instead of RJ11.

    7. Avatar photo XGS Is On says:

      Over 40 years ago the telecomms market was very different from now. Many other nations followed the UK in using that socket and the UK had a lot more clout. Now we’re 70 million in billions. The only three groups that set the regulatory trends are the USA, China and the EU. If we come up with a cunning plan one of them might follow and we’re good.

    8. Avatar photo anonymous says:

      XGS is On: “The UK isn’t important or large enough a market for our regulator to demand vendors from around the world conform to a standard we set.”

      This “we’re a non-entity on the world stage” argument seems quite popular with some people, even it’s wrong. The UK is easily able to (and does) set country specific standards in many areas, and as the UK is the 5th/6th largest economy in the world there’s plenty of manufacturers will be more than happy to comply with specific UK standards. I know this because I work for one of the UK’s standards regulators; we designate the standards to apply, we work with business and other stakeholders to create or modify those standards, and act to enforce them. Only last week I was talking to a gathering of UK and international industry representatives who stated that complying with UK standards is not a problem. If you’re a manufacturer who aims to supply more than one market, knowing the relevant standards and meeting them is a core competency, and a critical success factor is meeting multiple slightly different standards with a product that requires minimal change.

      Even for those without inside knowledge, the evidence is in your face every single day that the UK has specific standards and they don’t stop companies providing country-specific products, from UK mains standards and fittings, on cosmetics, chemicals, food standards, clothing standards, toy safety standards, vehicles, and a whole range of noise, environmental impact and performance standards. Things do work easily and ultimately costs are lower if standards are wider than one country, but the price of that is that the standards reflect the lowest common denominator, and improvement progress is always extremely slow; If a manufacturer has to meet multiple standards with the same product, the reverse often applies in it’s easier for the manufacturer to provide a product that meets almost all standards and so may beat their specific country or trading-bloc standards

      Having said all that, in the context of the thread I really don’t see much benefit in harmonising UPS standards and PSUs to supply ONTs and routers – the kit already plugs together just fine for those who want it to, and introducing new standards would increase complexity for virtually no benefit. The EU decision to force Apple to use USB C is a case in point – Apple had to re-tool and modify products to meet a very poor standardisation policy that has few if any benefits. If the same logic had been applied when USB was first a thing, then we’d be stuck with the nasty, nasty micro-USB forever, and phones that take 12 hours to charge. Speaking as a regulator, standards can sometimes be vitally important to deliver good outcomes, but they’re also a tool that needs to be applied thoughtfully and economically to avoid driving the wrong outcomes and stifling innovation.

    9. Avatar photo x_term says:

      @Just a thought It’s not about the layer 1/2 vendors, trust me. In Italy lines have been digital since FTTC (no option of analog line with those, only with ADSL). The law of the regulator very simply states: if the customer wants to use their own equipment, since everything is a standard protocol anyways, ISPs are obliged to give the customer all needed credentials to connect, while of course being able to give up support past the demarcation device (depending on which technology you are, but right now the only exception is for the FTTP ONT, you can put whatever all in one device anyways on FTTC).
      It is actually EU legislation being implemented.

    10. Avatar photo Ivor says:


      Apple were already moving towards USB-C before the EU made any moves in that area. Their laptops have been all USB-C for a while, as were the iPads as they came up for redesign. Of course the supplied cable has also been a USB-C to Lightning for a few years as well. They’d said in 2012 that Lightning would be a connector for the next 10 years, and it looks like they were right. Maintaining two connectors is a poor customer experience.

      With rumours of higher data transfer rates + ability to connect an external display for camera monitoring (at least for Pro models), there are valid reasons to move to USB-C.

    11. Avatar photo anonymous says:

      But, Ivor, Apple are already in prospective trouble with the EU over decisions relating to the iPhone 15 implementation of USB C before it’s even launched. Some compromise will be thrashed out, but the core point remains the same – regulators don’t innovate, and more commonly they hold back progress if they set well-meaning standards that are not needed. In this case Apple’s previous decisions on connectors have caused no problem that their customers have voted against with their wallets, yet some berk decided that there was a problem, and that they know better than Apple what Apple’s customers want or should have. That’s simply misguided.

      As said before, regulation is what I do for a job, and I know better than most people that it’s a many-edged sword that’s very prone to unintended consequences, especially with the sort of mindless ideas like this. You don’t save the planet by (in theory only) stopping a few USB chargers going in the bin, when the real environmental impact is 99%+ the raw materials, and manufacture of the handset itself.

  8. Avatar photo Serf says:

    BT could in rural areas and areas with large numbers of older and vulnerable customers bring back public use phones with voice and internet terminals with their own independent mains power and solar power battery backup to display useful information, public messages and advertising as seen in larger cities.

    Bringing such public use phones with internet terminal access into rural areas could maintain telephone and internet access during extended periods of mains power outages.

    1. Avatar photo The Facts says:

      Something parish councils could fund.

    2. Avatar photo Ad47uk says:

      @The Facts, so more public money. what Openreach/Bt should do is find a way to sort this out.

    3. Avatar photo Ivor says:

      Sort “what” out?

      The reality is that most people with PSTN lines (and who actually uses them) likely had them connected to cordless phones that would never work in a power cut anyway. A small UPS will get them through a typical power cut, and DV is likely an overall service improvement since the supplied cordless handsets will go days without a charge.

      BT has agreed to supply such a UPS to vulnerable customers, in line with Ofcom’s wishes. Other ISPs will do something similar.

      The idea of publicly accessible phones/computers would be over and above what rural people already get, and why would BT and Openreach solely fund it? If it makes sense to do, then it makes sense for government to operate it and slap a tax on whoever it feels should contribute to its cost. Perhaps they could bring libraries back to the places that lost them.

    4. Avatar photo 125us says:

      Are you expecting the makers of cookers, freezers and washing machines to also provide communal services for free for the days where the power company can’t do their job, or just telcos?

  9. Avatar photo Ad47uk says:

    So in other words, Openreach is saying tough luck and we will carry on doing what we want.

    1. Avatar photo XGS Is On says:

      Openreach aren’t saying anything. Only mention of Openreach is your comments.

    2. Avatar photo The Facts says:

      Ad47uk – how do you think CityFibre, Virgin Media, Gigaclear and all other FTTP providers etc., etc. works?

    3. Avatar photo 125us says:

      Do you complain to the manufacturer of your freezer when a power cut goes on for days and your food is ruined? Why is the inability of a power supplier to do their job the fault of a telco?

  10. Avatar photo Charles Smith says:

    I’ve dual routed broadband connections, with a 4G dongle backup. All elements of my LAN (wired/WiFi) are powered from UPS and I have an inverter petrol generator 230V on standby. Even so, last Thursday I lost the network for 24hrs.

    I’d failed recognise the dangers of a new puppy chewing the low voltage cable from the single and only wall PSU to the main router. I didn’t have a spare PSU on hand, but Amazon delivered in 24 hours. The puppy survived and has stopped chewing unpleasant tasting cables.

    Let’s hope the cell towers and street boxes have alternate power supplies to handle regional outages/storms.

  11. Avatar photo Optimist says:

    The landline socket in my house is now supplied by the HUb4’s TEL1 port. It drives the PSTN phone just as the exchange line did previously, so my household to make and receive calls. There is only one subscriber number regardless of the PSTN phone used. Not VOIP.

    The devices on my LAN include my laptop, which I use for Zoom calls, and smartphones which, when used at at home, connect via Wi-Fi. The smartphones have their own numbers. This is VOIP.

    So VMO2’s 21CV is not VOIP at all. Is BT’s Digital Voice any different?

    1. Avatar photo Ivor says:

      What makes you think “it’s not VoIP”?

      VM are likely using PacketCable – which is SIP based VoIP. BT’s service is also SIP based VoIP. The IP part may not extend beyond the router, but that doesn’t mean it’s not VoIP. Just as VoLTE on your mobile phone is VoIP.

      The BT version is probably better implemented overall, as you get HD voice and multiple concurrent calls and other bells and whistles that VM do not provide.

    2. Avatar photo XGS Is On says:

      ‘VM are likely using PacketCable’

      Yep – dedicated 128 kbit/s symmetrical service flow.

    3. Avatar photo Alex A says:

      They have the same user experience of just plugging a standard phone into the back of the hub/router. BT uses VOIP from the hub while VM operate (or at least used to) a seperate rf feed for the phone.

    4. Avatar photo XGS Is On says:

      It isn’t separate RF it’s a separate service flow on the same channels the broadband uses. Same channels, same RF, same everything bar a logical separation that gives the VoIP preferential access to bandwidth over the regular broadband.

      Pick up the phone you get reserved bandwidth until you replace the handset.

    5. Avatar photo Optimist says:

      The reason I say 21CV isn’t a VOIP service is that as far as the user is concerned, it is just PSTN via the hub (PSTNVTH?). I appreciate it uses IP under the hood, but whenever the term “internet protocol” is used non-experts think “oh it is an internet service, that sounds complicated.”

      It would be better IMO to reserve the term VOIP for internet telephony proper i.e. devices connecting via local area networks and the internet.

    6. Avatar photo Roger_Gooner says:

      @Optimist: It isn’t IP under the hood as PacketCable is used for things like QoS, but all traffic is still transmitted in DOCSIS frames on downstream and in Ethernet frames on upstream. It’s only when VM switches to an IP network will there be VoIP.

    7. Avatar photo 125us says:

      It is VoIP. Your call is using RTP/SIP via call servers. The end device you use is irrelevant. Your hub is presenting you with an analogue service emulation. VoIP is the correct term.

    8. Avatar photo Optimist says:


      Thanks for the technical gen. Regarding the switch to an IP network, will this mean VMO2 customers being able to use “real” VOIP phones connected via the home LAN, instead of PSTN phones plugged into the hub?

    9. Avatar photo Roger_Gooner says:

      @Optimist: Correct, we will use VoIP phones on an IP network. What we have now is an interim solution whereby voice traffic is carried in the same way as broadband, TV and VOD traffic is carried while VM works towards its holy grail of an all-IP network.

  12. Avatar photo Alan Smithee says:

    I keep deferring mine so that I can run out the contract and then switch to a proper VOIP provider alongside my FTTP as I don’t want to plug in their router at all.

  13. Avatar photo MilesT says:

    Re security pendants: Mobile phone based (multi-network SIM) with internal battery backup are now commonly available; if you have a monitored unit that still uses a landline connection then get the monitoring company to swap it. Ditto alarm lines and similar.

    Still needs the nearby towers to stay powered, though, and that’s where OfCOM needs to get the industry to focus–better backup power for the towers.

Comments are closed

Cheap BIG ISPs for 100Mbps+
Community Fibre UK ISP Logo
Gift: None
Virgin Media UK ISP Logo
Virgin Media £26.00
Gift: None
Shell Energy UK ISP Logo
Shell Energy £26.99
Gift: None
Plusnet UK ISP Logo
Plusnet £27.99
Gift: None
Zen Internet UK ISP Logo
Zen Internet £28.00 - 35.00
Gift: None
Large Availability | View All
New Forum Topics
Cheapest ISPs for 100Mbps+
Gigaclear UK ISP Logo
Gigaclear £17.00
Gift: None
YouFibre UK ISP Logo
YouFibre £19.99
Gift: None
Community Fibre UK ISP Logo
Gift: None
BeFibre UK ISP Logo
BeFibre £21.00
Gift: £25 Love2Shop Card
Hey! Broadband UK ISP Logo
Gift: None
Large Availability | View All
The Top 15 Category Tags
  1. FTTP (5515)
  2. BT (3514)
  3. Politics (2537)
  4. Openreach (2297)
  5. Business (2262)
  6. Building Digital UK (2244)
  7. FTTC (2043)
  8. Mobile Broadband (1973)
  9. Statistics (1788)
  10. 4G (1664)
  11. Virgin Media (1619)
  12. Ofcom Regulation (1461)
  13. Fibre Optic (1395)
  14. Wireless Internet (1389)
  15. FTTH (1381)

Helpful ISP Guides and Tips


Copyright © 1999 to Present - ISPreview.co.uk - All Rights Reserved - Terms , Privacy and Cookie Policy , Links , Website Rules , Contact