Power cut help
Digital Voice battery backup
The UK is moving every landline onto broadband. It's a good upgrade, with one catch: no power means no phone. This guide explains what changes and how to keep the line on.
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What changes with Digital Voice
The old copper telephone network (PSTN) is being switched off, and phone calls now travel over broadband. Your phone plugs into the hub instead of the wall socket.
Call quality is often better and the number stays the same. But because the hub needs mains power, a power cut takes the phone line with it, including the ability to call 999.
What Ofcom requires
Ofcom guidance says providers must offer a free solution so customers who depend on their landline can call emergency services for at least 1 hour in a power cut. You usually need to ask for it and explain why you depend on the landline.
Many households don't qualify, and 1 hour is short for a storm outage. That's the gap a hub battery backup fills.
LineKeeper™ Hub Battery Backup
4+ hours of backup · fits in 60 seconds · free UK delivery · 90-day money-back
From £89
Digital Voice backup options
How the main ways of keeping Digital Voice on compare.
| Option | Cost | Runtime | Wi-Fi too |
|---|---|---|---|
| Provider solution (if eligible) | Free | At least 1 hour | Varies |
| Office UPS | Varies | Varies, bulky and noisy | Yes |
| LineKeeper | From £89 | 4+ hours | Yes |
How LineKeeper helps
LineKeeper sits between the hub and the wall. It switches over in zero seconds, so the hub never restarts and calls in progress don't drop. Its 74 Wh battery keeps a typical hub running for 4+ hours, and it recharges itself when the power comes back.
How long will the backup last?
LineKeeper has a 74 Wh battery. A typical UK broadband hub uses roughly 10 to 15 watts, which gives 4 hours or more. Powering a separate fibre box as well, or an older hub that uses more power, shortens that. Fewer connected devices make it last longer.
For comparison, providers only have to offer a solution that lasts at least 1 hour. Many UK power cuts, especially in storms, last longer than that.
| What LineKeeper is powering | Typical runtime |
|---|---|
| Modern broadband hub only | 4+ hours |
| Hub plus separate fibre box | Less than hub alone |
| Older or high-power hub | Less than 4 hours |
| Provider minimum (Ofcom guidance) | 1 hour |
Is LineKeeper right for your home?
It's a good fit if: your phone now plugs into your broadband hub; someone at home relies on the landline or a pendant alarm; mobile signal is weak where you live; or you buy for a parent who lives alone.
It's not the right fit if: your hub's plug label doesn't say 12V; you need to power a computer, TV or fridge (LineKeeper is made only for hubs and fibre boxes); or your alarm already has its own mobile (SIM) connection and you don't use the landline.
Not sure? Try it for up to 90 days. If it doesn't suit you, send it back for a full refund.
How to fit it, step by step
- Charge it. Plug LineKeeper into the mains and let it charge fully. It stays plugged in from then on.
- Check the plug label. Look at the label on your hub's power plug. If it says 12V, LineKeeper fits.
- Connect the hub. Unplug the hub's power lead from the hub, plug it into LineKeeper, then plug LineKeeper's output lead into the hub.
- Add the fibre box if you have one. If a separate white Openreach box on the wall also has a power lead, use the splitter lead in the box to power both.
- Plug in a corded phone. Keep 1 corded phone plugged into the hub's phone socket. Cordless bases need mains power, corded phones don't.
- Test it. Switch the socket off at the wall. The hub lights should stay on and you should still get a dial tone.
LineKeeper™ Hub Battery Backup
4+ hours of backup · fits in 60 seconds · free UK delivery · 90-day money-back
From £89
Sources and further help
How we write our guides
Written by the LineKeeper team in plain English. We check facts against Ofcom, Openreach and provider guidance, and update guides when the rules change. We sell the LineKeeper Hub Battery Backup, and we say when it isn't the right fit. About us.
Related guides
Helpful answers
Frequently asked questions
Straight answers to common questions about digital voice battery backup.
Can I still call 999 in a power cut with Digital Voice?
Only if your hub has backup power, or from a charged mobile phone with signal. LineKeeper keeps the hub on so 999 calls work from your corded landline phone.
Does Digital Voice work without broadband?
No. Digital Voice uses your broadband connection and hub. If the hub has no power, there's no phone service.
Do I need an engineer to fit it?
No. Fitting takes about 60 seconds: move the hub's power lead into LineKeeper and plug LineKeeper into the hub. No app, no settings.
Is there a guarantee?
Yes. Every order has a 90-day money-back guarantee and free tracked UK delivery.
Keep your line on through the next power cut
From £89 (was £178). Free tracked UK delivery, 90-day money-back, fits in 60 seconds.
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