Maybe there is a reason why your monitored alarm wont work but for what it is worth; my alarm is NOT monitored but it does works fine. I did connect the router to my master phone socket myself (contacting VM is always such a waste of time in my experience) so all my existing extensions work. I can receive and make handsfree calls from my alarm control box and it calls me if the alarm is triggered and I can control it from the remote phone, listen in, turn it on and off etc. Works exactly the same as before, not sure why it wouldn't. Again though, maybe there is something about your monitored system other than needing to wire-up extensions. The only problem I have is the internet going down on a weekly basis so obviously nothing works, can't call faults, 999 etc, whereas in the past, 9 times out of 10 times when tv/internet failed the landline would still work. Also the people I have spoken to at VM have not been willing or capable of enabling voicemail (despite it being an advertised feature) for when it is down and vulnerable relatives need to contact me.
