The function Incoming call simplifies the entry of service notifications. As a result, when a customer calls, the system determines the technical objects assigned to the customer and proposes these to the person entering a notification as an entry tool.
You must activate and define the component SAPphone in the Customizing of Basis, so that Service Management is involved.
You must use the central address management in technical objects. This is the case if you specify addresses in pieces of equipments and functional locations.
Make the settings in the Customizing of Basis.