Hi all, any help appreciated. We have an old Visonic burglar alarm with no instructions and not sure of serial number. It’s worked fine for ten years or so and we have fumbled our way through the menu when a problem has arisen. Now we were testing if we could use it without a landline as wish to go the 4g route instead. So question is, A can these alarms BASICALLY work without a land line, I know it won’t text or phone you notifications, but will it make a noise. And B - Help, since testing by disconnecting from the landline via a little box that’s connected to the landline mastersocket it won’t work, the orange light is on and it says trbl on the screen. Any help given will be truly appreciated!