Abstract: A universal coupling unit for linking processing systems incorporating computers or processors with at least one peripheral unit. Each processing system has at least one processor and an exchange bus for exchanging information with the peripheral unit. The coupling units comprise bus controllers connected respectively to the exchange buses and to a local bus, itself connected to the peripheral unit by circuits for controlling exchanges of data and for processing control and state information. The bus controllers are able to manage the access protocols to the exchange buses, the information exchanges on the exchange buses and on the local bus, as well as any request made by a processor for access to the local bus. The control units comprise a microprocessor for managing the priorities of the access requests of the processors and the processing of controls and states contained in the information exchanged on the local bus.