Digital Voice with No Router, No Change or Extra Kit in Home, No Engineer Visit

[XRaySpeX]

Today my BT analogue landline was switched to Digital Voice w/out any home visit, use of router or any other new kit in home. It still uses my existing home phone sockets & internal wiring w/out any change. All the work was done at the exchange. All I had to do was change any short (7-digit) local nos. in my phones' phonebook to include the local area code. There is no cost associated with the switch & line rental & call plan are unchanged.

Previously in preparation for the eventual expected forced switch to DV via BB & a router I managed to persuade the OR eng who came to fix a fault about a month ago to merge my inactive 2nd master socket into my live 1st socket & internal wiring so as to be in easy reach of a router. Fortunately with this new "DV from the exchange" this turned our to be not entirely necessary.

This new "DV from the exchange" is called variously Dedicated Landline Service or Home Phone Standard. It it aimed at users with a landline who do not have BB. Of course, all this won't apply to EE users as EE does not offer a Landline Only service but is presented here for interest & info.

Calling Features can no longer be added or removed via the BT app but need to be requested by phone to CS who pass you onto a specialist Home Phone Standard team in Warrington. Indeed when you call BT CS you are connected with EE's BB CS who haven't the faintest idea about Home Phone Standard & confusingly start assuming you are on "DV via BB" & immediately tell you to reboot the non-existent router.

Unlike "DV via BB",  Home Phone Standard is impervious to power cuts.

Anybody got any idea how this is achieved at the exchange? I originally imagined that any landline users w/out BB would be given a simple small dedicated to DV router & put on Full Fibre but this did not come about & anyway I suspect would be unworkable if the user could replace the DV router by a generic one. Now I imagine the exchange contains some sort of DV multiplexing router serving a whole group of local users, effectively replacing the old POTS switchgear kit in the exchange.