Abstract
This paper presents new algorithms for the Signal and Message asynchronous data communication mechanisms (ACMs) and their modelling and analysis using Petri net techniques. This work extends the general knowledge of ACMs, the confidence of designing systems around them and the scope of their potential applications by standard Petri net techniques to model and analyse important properties of the new algorithms. The new algorithms and their proof also demonstrate that implementations of all types of ACMs can be found, and data communication within heterogeneously timed systems can span the full spectrum of asynchrony between processes.