Communication system with connectable interface element

Communication system (1), especially an IP network has a multiplicity of users (A-C) that are connected to each other via a communication line (10) and a number of connections (15A, 15B1, 15B2, 15C) for connecting a portable operating or visualization interface element (20). For unique identification of a connection between a interface element and a user the connection concerned a readable element that can be read by the interface element. The invention also relates to a corresponding interface element and a method for identification of a connection to a communications system.