Our organization is currently looking at upgrading our phone systems. We currently have 7 office sites around our state, which all have old key based phone systems. One avenue I would like to explore would be the deployment of the Open-Source Asterisk PBX software system. As with all Open Source solutions I am usually hesitant and would like to receive some responses from those of you have Asterisk currently deployed in your organization. Please be as detailed as possible and provide to me why you chose to use the software, what type of phones you are using, strong features which you love ..etc along with server specs for your installation. In addition how was the learning curve for the software, and how long did your implementation take.