My IT guys tried to build a FreeSWITCH which is based on the Asterisk platform. After a few months of work it was decided that it would not work for our application. Personally I was dead against it and all VOIP solutions. My Executone switch has been up and running trouble free for over 10 years. Never down for more than the time it took to reset once or twice over its life, compared to the computer network that would have sporadic outages that could last from 30 minutes to an hour or longer. I am still not sold on VOIP which is why i am leaning toward a hybrid approach. The computer guys can have their toy and i can still manage a reliable phone system.