On Saturday, 11 July 2020 16:29:01 UTC+1, JimK wrote:
(I appreciate it wouldn't work if the 4g internet was down.)

Many of the ATA boxes have automatic fall-over to PSTN if the VoIP fails.

If your mobile phone has Bluetooth you can pair it with one of these to make landline calls using mobile minutes (not VoIP).

https://www.ligo.co.uk/ligo-bluewave...ct-description

Owain