@pjohng it depends on the alarm you have. If it connects via wifi it will operate as before. If it uses the phone line to connect it becomes more complicated and if you order a full fibre connection the agent will talk you through the options.
In essence with Ultrafast and indeed almost all new broadaband services the phone connection switches from being through traditional phone sockets to a voice service via the Sky hub which will have a phone socket on its back. This will allow connection of a traditional phone or alarm but only works if the hub is powered and connected. The old copper based phone lines carried a voltage that meant phones and alarms worked during a power cut. Newer alarms are designed with battery back ups and even have built-in sim cards that work when the internet is down.
The copper phone system is being de-commissioned but there are various workrounds including changing alarms etc being developed but not everything is in place yet. Currently Sky wont accept an order for a Ultrafast service if they think your alarm would not function properly.
=========================================================
65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
