| 摘要 |
<p>PURPOSE:To rapidly inquire the fault point by discriminating as a disconnection of signal line when the output signal level of the OR circuit changes responding to the change of level of the data signal. CONSTITUTION:When either one of the two signal lines 2a and 2b that form a transmission line 2 becomes disconnected, the input signal to a disconnection detecting terminal F turns to be a periodic signal of a period of (T+T1), but when the both lines become disconnected, the input signal of the terminal F becomes constant at H-level. Therefore, by detecting the kind of the input signal to this disconnection detecting terminal F of the input port 8, an occurrence of disconnection and whether the disconnection, when occurred, is in one or both of the signal lines are able to be instantaneously discriminated by a terminal equipment 3 on the reception side. Further, the constant time T determined by the resistor 22 of a monostable circuit 21 and the time constant of a capacitor 24, is set sufficiently long in comparison with the cycle of the data signal so that the computer can easily discriminate. Therefore, the probability of misdiscrimination is reduced.</p> |
