are set thereby may be situated at any position within the block 38 for simplicity the user function is not further specified it is also possible that the internal scan test is not implemented but that the output of register 32 is directly connected to the input of register 36 register 32 in this example comprises six stages which can be filled in parallel via input 26 it can furthermore be filled serially via input 22 and the switches 42 and 44 provided these are in the appropriate positions the register 32 has a serial output to register 34 the register 32 has a parallel output to the block combinational logic 38 for testing the interconnection function a result pattern is received in parallel and is removed serially for testing block 38 a test pattern is received serially and is removed in parallel it is not strictly necessary for these two provisions to be implemented register 36 in this example comprises six stages which can be filled in parallel from the block combinational logic 38 it may furthermore be filled serially from register 34 the register 36 can provide its information serially to output 24 provided switches 46 and 48 are.