I had this working in a lab about 3 years ago. Did it just to see if it would work. As I remember there were some difficulties with getting all of it to work properly. Additionally, I had a customer want to add a temporary sales office for about 50 telemarket people. Rather that pay the license fees to get all of what the customer wanted to a six month period, we connect an Asterisk box up with a PRI. This worked great.