On Thursday, 21 November 2019 15:11:46 UTC, Andrew wrote:

But those green cabinets have a power supply (and a non-smart meter !!)
so they could still supply DC from there (in theory).

One near me has a smart meter with dedicated analogue telephone line
connected to the meter. It also has a large SLA 48V backup battery
made of four 12V batteries I think.

Once everyone has been moved to VoIP there will be no need for
many exchanges so they will probably be sold. Around here, for example,
the fibre from each green cabinet goes to a different exchange to the
copper. So once the copper is no longer needed, one of those exchanges
is also redundant.

John