Data communication apparatus

摘要

A data communication apparatus adapted for use as a train describer system has a multiplicity of modules serially connected in a closed loop, each such module being arranged to transmit data to, and receive data from the two adjacent modules in the loop, a plurality of the modules located at spaced positions around the loop also being "interconnection" modules adapted to transmit data directly to and receive data directly from the adjacent interconnecting module or modules of the plurality.