Thanks to all who replied. Much clearer now.
I'm now scheduled for connection to digital voice on 13 Februrary, and a further question has arisen.
Referring to WSH's third and last diagram (Digital Voice with full optical fibre), what do I use for the wired connection between the phone socket on the Smart Hub 2 router, and the phone socket on the wall (which happens not to be the master socket)?
An Openreach person told me to ask BT for a "wired digital voice adapter" but they sent me a wireless adapter instead. It seems now that BT used to supply such a wired connection, but no longer do so.
Is there anywhere that one can be obtained? Or perhaps I could have one made up? If I'm not making sense, is there a description of the connection I need anywhere on the internet?
Thanks for your advice.
You simply need a double ended BT431 - BT431 cord. Obtainable from usual sources.
As has been explained many times on the thread.
The easiest would be a BT plug to BT plug lead from the green socket on the hub to the phone socket closest.
Edit: Oops, Licquorice beat me to it.