| 摘要 |
PURPOSE:To automatically switch artificial lines to a standby line so as to make the switching time shorter and operation simple, by correcting the artificial line of a standby device to the distance of the artificial line of a presently used device when switching to the standby device. CONSTITUTION:Presently used plural artificial lines 22 and 23 and a standby artificial circuit 24 are connected with the control section 13-1 of a multiplexer. When setting is made to correct the presently used lines 22 and 23 to desired distances, one level is outputted from the (a) of a decoder 25 under the control of the control section 13-1 and a 100-field artificial circuit 16 is manually earthed so as to insert the circuit 16. Then relays RL1 and RL2 are operated by the output of a logical circuit and the circuit 16 is inserted by means of the contacts rl1 and rl2 of the relays RL1 and RL2. When a 200-field artificial circuit 17 is inserted, the (e) is manually earthed and, in the same way, the circuit 17 is inserted by the contacts rl3 and rl4 of relays RL3 and RL4. By automatically switching the circuit 24 to the circuits 22 and 23, the switching operation is made simple and switching time is made short. |
