| 摘要 |
<p>PURPOSE:To adopt a unit for an automatic switching control circuit together with a transmission circuit and to miniaturize a circuit by arranging a changeover switch, a fault detection means and a control means to each of 1st or 2nd termination circuits respectively. CONSTITUTION:First termination circuits 1-4 terminating each of 1st signal paths 11-14 and a 2nd termination circuit 5 terminating a 2nd signal line 15 switched when the 1st termination circuits 1-4 are faulty are provided. Then the 1st or 2nd termination circuits are provided with fault detection means 21-25 detecting the fault of the termination circuits, a changeover switch switching the 1st signal lines 1-4 into the 2nd signal line 15 when the termination circuits are faulty and a control means controlling the changeover switch based on fault information coming from a fault detection means and a subsequent termination circuit and also sending fault information to a host termination circuit are provided. Thus, a unit is adopted for the automatic switching control circuit together with the termination circuit and the circuit is miniaturized, then the addition or revision of an input/output signal line is flexibly coped with.</p> |
