Replacing our SIP doorbell with a plain, old-fashioned, doorbell

Just over six years ago, I installed a shiny Fanvil i10 SIP doorbell. It was little more than a SIP phone in a doorbell box (as the configuration options made clear), but I wanted something which would ring my phone and Sandra’s phone when someone rang it, wherever we were, and I wanted it to go as SIP/RTP, rather than using a proprietary app. So I installed it, popped it on its own VLAN (because I had to run an ethernet cable to the outside of the front door), configured it to talk to our PBX, and went with it. I didn’t bother with the video side of things. And, for those six years, it has been fine, ringing our phones whenever the doorbell was pressed. Recently, calls from the doorbell have been intermittent in their success in calling Sandra’s phone, whether terminating via SIP client, or routing a call to Sandra’s cellular network. And, sure, I could probably spend the time debugging it, but I was trying to solve a problem which didn’t really need solving: we just need a button…