IP based panic button

[ArchAnGeL]

I am looking at work on how we can have basically a panic button (the liklihood of using it is very low)
We have and IP phone network.
The simplest idea I can think of is to have something sat on the network that can be dialled from any of the IP phones e.g. 8888 and will trigger an audio file to play over the intercom

Does anyone have any experience of such a system or other ideas? Sounds pretty easy if nothing exists but I would imagine it does


Thanks