A circuit arrangement for connecting a bus participant to at least one bus, having an interface for connecting the bus participant to the circuit arrangement, a first bus input, and a first bus output between which the bus participant is switchable via the interface. The circuit arrangement includes a second bus input and output for connecting the bus to the circuit arrangement in a ring topology in such a way that the first bus output is connected at least indirectly to the second bus input and the second bus output is connected at least indirectly to the first bus input via the bus. The bus in the circuit arrangement can be separated to obtain a line topology and can be configured as bus-terminating at one of the bus inputs or bus outputs. A system for the functional testing of bus participants on a bus in a simulation environment is provided.