An example test system includes a bus interface to connect to a bus of a computer system; and test instruments to perform one or more test operations on a UUT, where the test instruments connect to the bus interface to enable communication between the computer system and the test instruments via the bus interface. At least one test instrument includes: ports to which the UUT is connectable, with each of the ports interfacing to a corresponding peripheral bus supported by the at least one test instrument; circuits to connect the bus interface to the peripheral buses, with each circuit being configured to convert between a bus interface protocol run on the bus interface and a peripheral bus protocol run on a peripheral bus; and a switch to identify a target circuit of the circuits, with the switch to direct communications between the computer system and the target circuit.