@kezo it’s a Texecom.
Texecom Monitor provides a digital solution and likely to be cmpatable with your current monitoring. BT’s digital voice adaptor (available from BT £20ish) and is known to work with existing PTSN equipment. The downfall is it needs to be plugged into an existing socket and the phone connection from your alarm plugging into it which is not what I’d class as high security but, perhaps you have a cupboard nearby with a socket in and can disguise it.