Digital Voice: I have a problem with my battery back-up unit (BBU)

Your Hub must have power for you to be able to make calls using our Digital Voice service. You can buy a battery back-up unit (BBU) when ordering Digital Voice. This means that both broadband and voice services will continue to work for at least an hour if there's a power cut.

Please make sure you keep your battery back-up unit connected to the mains power supply and your Hub powered up. This will make sure it has enough charge if it's needed.



What it means

System Status Green The battery back-up unit is working as normal.
DC Green The battery is supplying the power. When it reaches 45% capacity, the light will flash and the alarm will beep four times a minute.
Mute Orange The battery back-up unit has been silenced. Press and hold the Alarm Silence button for half a second to turn the volume on or off. The light will flash to confirm the change. This will only silence the alarm for 24 hours.
Battery Red The battery needs to be replaced. The alarm will beep once every 15 minutes. You'll also see this light when the battery's missing.


You can check your battery back-up unit is working by turning it off at the mains socket and checking that your Hub's blue light stays on. Don't forget to turn the power back on again. We recommend you do this once a month. 

If your battery back-up unit starts to beep, check it hasn't been disconnected from the mains power by accident. If it continues to beep and you also have a red light, the battery needs replacing. Please contact us so we can send out a replacement.

If it starts to beep during a power cut, don't worry. You'll still have at least an hour to make calls. 

Fix your Digital Voice service with our troubleshooter

You can test your connection, report a fault with the network and fix a wide range of Digital Voice problems using our troubleshooting tool >

If we can't find a fault or fix the problem online, we'll give you the option to book an engineer appointment.

If you can't connect to your BT Broadband, you can also do all of this using your mobile internet connection.

Already reported a fault?

Track your fault, change contact details and appointment times using our fault tracking service >

Still having problems?

Visit our contact pages for other ways to get in touch. 

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