We have a design in which we have some industrial ethernet switch which support FXS port, This industrial Switches are connected back to L3 Core Switch. This inturn connected thorugh the VOice trunk Gateway to the PBX via a E1 line. I need to know is there a requirement of call manager in this design? which to be connected to the core switch for call routing or will my design satisfies a VOIP network
note: i am connecting only analog phones in this design there is no IP phone.