Abstract: A system is disclosed for generating test data for testing logic circuits. It has a store storing a respective Logic List for each of the basic logic circuit types in the form of a list of logic states identifying terminals of the logic circuit to which specified data inputs are to be applied and terminals at which specified data outputs are expected.Another store generates connection information relating to a particular logic circuit under test and specifies any external conditions applied to that circuit by means of its terminals which modify its operation. Means are provided which then modify the logic states of the Logic List in dependence on the connection information, so as to produce a final set of test data which can be used immediately, or subsequently, to carry out the tests on the particular logic circuit.

Abstract: By means of contact pins fixed on a plate, test signals may be applied to points in a logic circuit to be tested, the signals being applied for such short periods of time as not to damage components in the circuitry. High speed switches can be individually enabled so as to pre-select any particular one or ones of the contact pins, and a pulsed voltage source then momentarily energizes the pre-selected pins. Output signals are read via other switches connected to the contact pins. The high speed switches are electronic. Control means controls the switches in accordance either with pre-programmed information or with information fed in. In the latter case the fed-in information is then automatically transferred to enable it to be used again if that circuit type is tested in the future.