Thanks Andrew, Denis and Bueller.
Old guy, not tech savvy, so I’ll do my best to answer.
Wiring unchanged from when adsl first connected several years ago.
Only got one phone
Original phone plug, Jackson 3 pin screwed to the wall.
Internet connection several years old now and ditched crappy Optus modem years ago.
I am currently running internet with phone disconnected and without filter to minimize any disruption.