Every so often the system will activate the PagePac a tone is heard over the speakers and if someone is on any phone they will hear the tone over the handset and in some cases the call will be disconnected. I've replaced the PagePac and checked programming. Anyone ever heard of this?

Merlin Legend v10 two cabinet

It could be a failing MLX phone with a bad flex board in it.

Thanks Ttech. I think you are right.