Colloque avec actes et comité de lecture.This paper discusses the main paradigms on fieldbuses from the applications requirements to the most common solutions derived to fulfill them. Temporal properties of the data to be exchanged are analysed. Data are classified according to their criticality and their transmission frequency, for each of these types, the communication requirements are identified with emphasis on the real-time aspects. Two architectures are identified in order to design the applications, and an overview of their characteristics is presented. Main paradigms on fieldbuses are analysed at different levels of the architecture and in different contexts: synchronous vs asynchronous, periodic vs aperiodic, centralized vs distrib...