3 wire phones

[brianposter]

3 wire phones -  Has anyone any idea as to how many 3 wire phones might still be in use ?

[WSH]

I doubt if anyone knows.

Are you having difficulty getting an old phone to ring?  If so, I’m told plugging the phone in with a microfilter gives it a third wire.

[chrisjp]

It does and this enabled my old 3 wire phone handset to ring when plugged into a BT DV adapter

[brianposter]

Presumably somebody would have tried to find out prior to the fibre switchover. Even a very rough estimate would be interesting - dozens, thousands, millions ?

[chrisjp]

Since 3 wire phones can easily be made to work with both analogue and digital voice phone systems, I guess there hasn't been much incentive to find out how many of them are still in use

[brianposter]

Given that BT fault reporting suggested that I buy a new phone and apparently had no idea how to make an old one work, I am wondering how much has been wasted on replacing old phones unnecessarily.