Showing results for 
Show  only  | Search instead for 
Did you mean: 
Message 1 of 1

How to connect a Battery Backup Unit (BBU) to your Smart Hub

We provide a Battery Backup Unit (BBU) to our vulnerable customers with Digital Voice, so their Hub can still receive power when there’s a power cut. This is so you can still make emergency calls from your Digital Voice phone or existing corded handset. 

You’ll need to make sure you've connected your digital handset to your Smart Hub or plug your corded handset into the phone port in the back of your hub.

If you would like to register as a vulnerable customer, visit our Here For You page.

Setting up the Battery Backup Unit to your Smart Hub


  1. Slide open the battery compartment of your Battery Backup Unit and remove the battery
  2. Slide the battery back in part of the way so you can connect the red wire to the red terminal
  3. Slide the battery in fully and replace the cover
  4. Plug the Battery Backup Unit into the mains using the power cable
  5. Turn On the mains power
  6. The Battery Backup Unit status light will show green
  7. Unplug the existing power cable from your Hub
  8. Connect the Hub to the Battery Backup Unit using the supplied Hub connector cable
  9. Your Hub light will show green, then amber, then finally blue once the hub is up and running

The battery takes 24 hours to become fully charged but you can still use your hub in the meantime.