We have two offices. One in NYC and one in LA. We would like to use VOIP in our offices. We have cat 5e cables installed in both offices. Can someone tell us or point us to what would be good VOIP solutions for us. We would like to use our current PBX systems(Panasonic KTX618 & Bizfon 680). If we do go with VOIP solution, we would get separate DSL or Cable service for VOIP. Thank you