Abstract. Asynchronous communications are prominent in distributed and mobile systems. Often consystems consider an abstract point of view with synchronous communications. However it seems more realistic and finer to consider asynchronous communicating systems, since it provides a more primitive communication protocol and maximize the concurrency. Several languages and models have been defined using this communication mode: agent, actor, mobile computation, and so on. Here we reconsider a previous component model with full data types and synchronous communications with an asynchronous flavour. The dynamic behaviour of a component is represented as a structured symbolic transition system with mailboxes. We also present an algorithm devoted to an analysis of the dynamic behaviour of the system. This algorithm decides if the system has bound mailboxes and computes the reachable mailbox contents of the system. The component model and the algorithm are illustrated on a flight system res...