You need to allocate a server to host your dialer. The server will function to route all incoming and outgoing calls and intercom. When you make a call from Volare or SIP Phone (described later), your PC will tell Volare server that you are initiating a call and Volare server will send instruction to this Dialer Server so that it can execute the call. It is also responsible for voice recording to be extracted later by Volare.
The channel bank (described later) will be connected to this server. You may opt for a cheaper server but it may cause a delay depending on the load (number of people making concurrent calls). A single processor server with Xeon X3450 processor with 8gb RAM and 500gb Hard disk space should comfortably accommodate 40 users with 30 concurrent calls.