In short: A BT digital phone line is a business number delivered over an internet connection rather than a copper line. BT's options include Cloud Voice Express, a digital line run through an app, Digital Voice for Business and BT Cloud Voice. Old analogue phones and extensions will not work directly, and digital lines need power to work.
What is a digital phone line?
A traditional business line is a copper pair from the exchange with a dial tone on it. A digital phone line does the same job, giving you a number that rings and makes calls, but the call is carried as data over your broadband using voice over IP (VoIP).
Openreach stopped selling new analogue lines in September 2023, and the PSTN switch-off date is 31 January 2027. So the question for most businesses is not whether to go digital, but which digital service fits. Background on the deadline is on our PSTN switch-off page.
Two things make a digital line different in practice:
- It needs a working internet connection. If the broadband is down, calls stop unless you have backup such as Hybrid Backup or calls diverting to mobiles.
- It is not tied to a socket. The number lives in the cloud, so it can ring on a desk phone, a computer or a smartphone app, in the office or elsewhere.
BT's digital line options
| Service | What it is | Best for |
|---|---|---|
| Cloud Voice Express | BT's hosted VoIP service for small businesses, managed through an app. It supports up to four numbers across up to four locations, and comes with the BT Business Fibre bundle, as an add-on to an existing BT plan, or as a digital line without BT broadband. | Small sites replacing one to four analogue lines |
| Digital Voice for Business | BT's Webex-based cloud calling suite in Essential, Enhanced and Extra packages, with a softphone app and optional desk phones | Small and growing teams that want phone system features |
| BT Cloud Voice | BT's hosted phone system with Basic, Connect and Collaborate licences, aimed at five or more users | Established teams, call queues and several sites |
| BT Cloud Phone | A fully configured, plug-and-play cloud phone option where every user has the same features, as BT describes it | Small businesses that want a simple set-up |
BT treats these as separate services. Digital Voice for Business, for example, is completely separate from BT Cloud Voice and Cloud Voice Express, so features and numbers do not move between them automatically. Our business phone systems page compares them in more detail.
Cloud Voice Express in brief
Cloud Voice Express is the closest like-for-like swap for a basic analogue business line. You keep a landline-style number, and calls can be made and taken from the office, from home or on the move through the Cloud Voice Express mobile app. The app also handles call diverts to a colleague or voicemail, diverts scheduled in advance, voicemail shown as text, and a personal or standard greeting.
Our sister site, which covers BT's Cloud Voice range in depth, has the full picture on BT Cloud Voice Express, including how it is bundled with broadband. BT also offers it as a standalone digital line if you are not on a BT broadband plan.
What changes when you switch
Moving from an analogue line to a digital one is usually straightforward, but a few things catch people out:
- Old phones and extensions will not work as they are. Analogue handsets, wiring that runs extension sockets round the building and older phone systems are built for copper. Expect to use the app, a computer or digital handsets instead.
- Digital lines need power. The router and any desk phones need mains power, and Openreach notes that digital lines may not work in a power cut without backup power. Keep a charged mobile available for emergency calls and consider a battery backup (UPS).
- Special equipment needs checking. Alarms, lift phones, card terminals, fax and franking machines may rely on a copper line. Check each one first, as set out on our PSTN switch-off page and on alarm and special lines.
- Your broadband may change too. Without a phone line, part fibre broadband moves to SoGEA, and full fibre (FTTP) never needed a phone line in the first place.
- Numbers move with a transfer. BT can transfer a number from a copper line onto a BT digital service, and port numbers in from other providers. Keep the old line active until the transfer completes.
Handsets, apps and smartphones
With a digital line, the phone is whatever device the service supports:
- Smartphone apps: Cloud Voice Express, Digital Voice for Business (Webex Softphone) and BT Cloud Voice all have apps, so a mobile on Wi-Fi or an EE Business plan can take office calls.
- Computer softphones: useful for staff at a desk with a headset.
- Digital desk phones: IP handsets that plug into your network. Each BT service supports its own range, so handsets from one service may not work on another. See BT Cloud Voice handsets for that range.
If your team lives on mobiles, read BT business mobile on how EE Business plans fit alongside your digital lines.
How we help you go digital
As a BT Business Partner, Forever Communications Ltd will list your lines with you, separate the ones that are really phones from the ones that serve alarms or terminals, check what broadband each site can get, and recommend the simplest digital service that does the job.
We then handle the BT order and the number transfers, so there is one point of contact from start to finish. Contact us and ask us for a quote.
Explore Digital phone lines
Why buy BT through Forever Communications
Forever Communications Ltd is a BT Business Partner, supplying BT Business connectivity, voice and mobile services to UK organisations. You get BT's network with a named team who knows your account.
- Impartial advice on the right BT product for each site, from Essential, Enhanced, Pro and Ultra business broadband to BTnet and BT Ethernet
- One point of contact for availability checks, orders, installations, moves, upgrades, faults and renewals
- Ready for the PSTN switch-off: digital phone lines, SoGEA, BT Cloud Voice, BT Cloud Phone and Digital Voice for Business, with your numbers kept where possible
- Multi-site and sector know-how for schools, GP surgeries, retailers, hospitality venues and growing offices
- Mobile and security too: EE Business mobiles from BT Group, Hybrid Backup on the EE Business 4G network, and BT security options alongside our wider Cyber Essentials help
We sell to businesses, schools, charities and public sector organisations. We do not sell consumer or home products.
Want a BT Business quote for your sites?
Tell Forever Communications what you need and we will come back to you by email with options, not a hard sell.
Contact usFrequently asked questions
What is a BT digital phone line?
It is a business phone number delivered over an internet connection instead of a copper line. BT's options include Cloud Voice Express, Digital Voice for Business and BT Cloud Voice, all of which can ring on apps, computers or digital desk phones.
Can I use my existing phones with a digital line?
Usually not directly. Old analogue phones, extension wiring and older phone systems are designed for copper. Most businesses switch to a smartphone app, a softphone or digital desk phones supported by the chosen BT service.
Does a digital phone line work in a power cut?
Not without backup power. The router and any desk phones need mains power, so a digital line stops working when the power goes unless you have a battery backup. Keep a charged mobile for emergencies, and consider a UPS for the router and key phones.
Can I keep my number when I move to a digital line?
Yes, in most cases. BT can transfer a number from a copper line to a BT digital service, and numbers can be ported in from other providers. Keep the old line active until the move completes.
Do I need full fibre for a digital phone line?
No. A digital line runs over any broadband with enough capacity, including full fibre (FTTP) and SoGEA. A stronger connection, or a backup, makes calls more reliable.