Embodiments provide an electronic circuit breaker subassembly and circuit breaker secondary electrical contact assembly. The hinge element or the bearing element can be produced from a plastics material. The management method includes user selecting respective presence states for one or more members or groups of members of the address book, transmitting the respective presence states to the members or groups of members and modifying the presence state relating to the user for each of the members or groups of members according to the received respective presence states. An equipment operator advantageously achieves superior controllability and quicker movement of equipment functions using the invention. The diaphragm defines a backside portion of the workpiece cavity.