I have tried to put a 5m telephone cable between the Hub and the Phone, but I get no dial tone. Are all cables wired the same? What am I doing wrong?
Presumably your phone setup works with the phone plugged direct into the hub via the short adapter lead?
What connectors are on each end of the 5m lead? If it has a standard BT telephone plug on one end and a standard BT telephone socket on the other then that should work normally. You need to try and test the individual parts of your system to try and see where the issue lies.
Are you able to take the 5m lead and test it on another landline connection (friend, family, neighbour)?
Are you able to bring another, known working phone to your own setup and test a different phone connected to your system on the end of the 5m cable?
Default arrangement for the hub telephone is shown in the bottom left pic here