Hi Furneaux99,
Thank you for your post.
Can you please provide some further clarity on your post so we can help? 🙂
Do you mean that you have two different phone lines with different landline numbers?
If that is the case, you should get a back up for the secondary line, as the Hub only supports one registered number.
If you're referring to an extension on your line, we can fit this for you.
More details on the homephone switchover can be found here
Thanks
Beth