We currently have a NEC NEAX 2000 (Site 1) serving our executive office with over 150 phone/fax lines being served via the PBX. This is currently sitting on a standard T1. We have a co-location (Site 2) which is served NEC Electra 192 which has 17 extensions for voice and several for fax. We've also implemented a multilink interface between both sites (Site 1 = 3mbps mpls, Site 2 = 3mbps mpls). Currently the phone systems are not ip enabled and we would like to acquire the interface cards for both systems but I have no idea how to get this off the ground. We would like to be able to dial the extensions from site 1 to site 2 and vice-versa. We would also like the trunk from site 1 to carry the fax lines and voice calls for site 2. The mpls is currently at 35% cap. I need soup to nuts help on this scenario. The routers between site 1 and site 2 are cisco 2821. Your help with this scenario would be greatly appreciated. Should we be using asterisk for anything in this scenario?