| 摘要 |
PURPOSE:To discover a faulty position in the early stage, by providing an optical display means, which displays the signal level of a signal bus, in a terminal circuit to discriminate the faulty position of a digital signal processing system. CONSTITUTION:An optical display means, for example, a light emitting diode D1 which displays the signal level of a signal bus 21 is provided in a terminal circuit 102. Then, the light emitting diode D1 continues not to emit the light if ground- fault occurs in the signal bus 21; and thus, the signal state on the signal bus 21 is detected by the flickering state of the light emitting diode D1. |
