Mobile phones are being increasingly equipped with sensors that ease retrieval of context information about a user. Context data can be aggregated with information centrally available to mobile operators and service providers, to infer higher-level information such as user “situations”, easier to integrate with services. We have been conducting an internal trial monitoring the context of different users in their business life and designing rules to infer high level situations: logical location, activity and social state. In this paper we present the infrastructure and the rulebased reasoning process used for this experiment.