We are the hosted provider, we have just never had to tie into an existing overhead paging system before. I was just looking at that exact Valcom part number the other day. I called up Valcom support and they confirmed that the VIP-802A would work for this scenerio. That is what I'm going to go with. Thanks all for the responses and input.

Also, in doing some Internet research, some people have used the SNOM PA1 to tie into paging systems. Anyone have any experience with those?