A communication system includes a plurality of network devices that communicate using one or more protocols, such as SIP. Graphical terminals (30) communicate with the network devices. Graphical servers (32) provide a graphical user interface for the graphics terminals (30) responsive to signaling messages received by the graphical terminals (30) and forwarded to the graphical server (32) in a service request. As the user operates the interface to perform functions, graphical information on the user's actions is sent to the associated graphical server (32). The graphical server (32) interprets the graphical information and updates the graphical interface and/or generates service requests for signaling messages to create, modify and terminate communication sessions as desired by the user, using the appropriate protocol.