This thesis focuses on systems for mediated communication that run on mobile technology. The aim has been to give an answer to the question about what require- ments there are for situation awareness for domain experts when communication is secondary and supports the primary task. This thesis originated in a critical approach to the common practice of design- ing mediated communication systems with the face-to-face meeting as a guiding scenario. Instead, this thesis explores a design process that is based on the task and the strength of the technology itself. Different tasks do, of course, make different de- mands on a system, and a task that is strongly connected to the face-to-face meeting will probably be best served by a system that is designed from that perspective. Three cases that are presented in this thesis share three common themes that have characteristics that set them apart from the face-to-face meeting. The first theme is that the communication is a secondary task that is used to support a primary task. The second theme is that the cases involve domain experts active in the primary task. The use of experts implies that communication will be task- centered and also that the need for information to sustain a valuable situation awareness may be different from a person with less experience in the domain. The third theme is that all cases and the corresponding tasks benefit from some kind of situation awareness among the participants for optimal execution of the task. The three cases are based on: Wearable computers using mediated communication with wearable computers and how to handle interruptions for users of such computers Multidisciplinary team meetings improving access to patient information and enabling individual and group interaction with this information Trauma resuscitation giving a remote trauma expert’s correct and valuable in- formation while minimizing disturbance when supporting a local trauma re- suscitation team Prototypes are central in all three cases, and different prototypes have been designed and evaluated to validate the benefit of designing tools for communication that do not try to replicate the face-to-face meeting. The main findings in this thesis show that the shift of focus to the primary task when designing mediated communication systems has been beneficial in all three cases. A conflict between the secondary communication that is used to support sit- uation awareness and the primary task has been identified. Full situation awareness should therefore not be a goal in these designs but communication should support enough situation awareness to benefit the primary task with minimal disturbance to it. / <p>QC 20140221</p>