A bus system includes a plurality of master devices each of which issues a transaction request having a first transaction identifier with a first bit width and a slave device responding to the transaction request having a second transaction identifier with a second bit width and supplying a transaction response having the second transaction identifier to the plurality of master devices. The embodiment further comprises a bus configured to connect one of the plurality of master devices and the slave device; and an ID converter configured to connect the bus and the slave device and to map the first transaction identifier to the second transaction identifier for providing the second transaction identifier to the slave device and map the second transaction identifier to the first transaction identifier for providing the first transaction identifier to the one of the plurality of master devices.