| 摘要 |
<p>PURPOSE:To prevent the formation of a closed loop (deadlock) of a control line, by making use of the fact that the transmission of control line is not required until the loop is released after a loop-back controlling signal is transmitted. CONSTITUTION:In a normal working state, a latching circuit 5 is set first with transmission of a loop-back control releasing signal TF. Therefore a control signals CONT1-CONTm are transmitted to a device B regardless of the presence of gate circuits 6 and 6-1-6-m, respectively. When a loop-back controlling signal L is transmitted, the circuit 5 is reset. Then the signal TF is transmitted again, and the circuit 5 is set. Meanwhile, the circuits 6 and 6-1-6-m are closed to inhibit transmission of control signals including the signal LP.</p> |
