Provided is a semiconductor memory device, which realizes characteristic evaluation even in a case where a threshold voltage is a negative potential by a test method which is similar to a case of a positive potential. The apparatus uses a cam portion opposite a hook portion in a structure of one of the objects to engage with flanges, protrusions or ends of the other object. Control signals are selectively applied to the control terminals of the transistors to control the switch and selectively turn on or turn off each of the three circuit paths depending on the input voltage range, so that the breakdown voltage of all of the transistors is never exceeded in any mode of operation. The plurality of devices being arranged to process the input signal to create an output signal which has a SONET payload. The novel compounds have plant-protecting properties and are suitable for protecting plants against infestation by phytopathogenic microorganisms.