There is a way to convert people off the old , soon to be retired PSTN network without broadband to newer IP style telephony ( BT call their IP telephony Digital Voice ) , without the customer getting any new equipment at home …basically instead of any new equipment being provided at the customer end of the ‘line’ it’s provided at the exchange end (it’s not just a BT router/hub at the exchange but the technical details are somewhat irrelevant , it’s not regular DV )
…the changes were in part so the customer doesn’t need local power and a broadband router at home (obviously that’s susceptible to power outages ) , but a change the customer does need to be aware of is the need to ring the full national number , even on ‘local’ calls , apart from that from the customer perspective nothing else is needed and it should be a seamless change .
If your mother has been connected to this transitional product , then any problems can be tested for (and detected) in the same way as the previous PSTN service , so calling and saying my line is faulty, BT testing it and deciding if the fault is detectable, is no different to previously, however it’s conceivable that the new interface is faulty but it’s unlikely…
if your mother had at some point in the past had the normal ‘automatic gain’ setting changed to a fixed level (something done very occasionally when customers complained the volume was too low, usually it was their hearing that was impaired ) chances are this can’t be replicated with this new transitional product (and TBH without anyone without a hearing impairment would say it’s too loud if the automatic gain setting was changed to a fixed setting, it was so rare chances are it’s not going to be remembered as a thing that was occasionally used for ‘quiet’ lines .
If possible, it may be wise to get someone else to try this to verify if the volume etc is acceptable for the average user , if it is , your mother may need something like an amplified handset .
