Abstract: A network for switching messages between a plurality of processing units, each of the processing units being connected to a transmission channel. The network includes a plurality of input interface devices which can memorize a plurality of messages and furthermore is also adapted to output and access requests onto a common bus. When one of the input interface apparatuses receives a consent signal, it outputs a message onto the bus. This message is memorized by the output interface devices with an indicator that coincides with one specified in a predetermined byte of the message. In addition, a scanning apparatus is provided for forwarding address bits to a multiplexing device.