NECA TR-28 is a technical report of the Japanese electrical control equipment manufacturers association, and it defines a noise test that occupies a distinctive place in Japanese practice. The disturbance it specifies is a rectangular pulse with a rise time shorter than one nanosecond, applied through a coupling network to the power and signal circuits of control equipment. It differs from the fast transient burst test of the international standards in the shape and the amplitude of the individual pulse and in the coupling arrangement, and it is more severe at the highest frequencies, which means it is particularly effective at revealing the behaviour of a design at the frequencies where the parasitic elements of a printed circuit board determine the outcome. The method is widely specified by Japanese customers for programmable controllers, inverters and factory automation equipment, and a supplier to that market will frequently be asked to demonstrate immunity to it in addition to the international tests. The rise time of the pulse is what makes the test demanding to perform as well as to pass.