Abstract: A data exchange system for use in a system that includes a plurality of redundant channels (12). A data exchange unit (30) is provided to process data, ensuring that consistent data are used by each of the channels. The data exchange unit votes the data so that an output is provided that is identical in non-faulty channels. The data exchange units communicate over an inter-channel net that includes a consistency port (160), which serves as a separate second fault containment region for each channel, enabling the data exchange system to be Byzantine resilient. If input data are provided by a single one of the redundant channels, the data are distributed to each of the data exchange units for all channels in the system using two rounds of communication. However, if nominally identical data are input to each of the data exchange units in the redundant channels, a single round of communication and a simple voting process are used to determine a consistent output for each channel.