| 摘要 |
<p>PURPOSE:To constitute a transmission system having an optional number of transmission lines of without wastefulness by equipping an alarming signal outputs and a control inputs with plural transmission line monitoring circuits and connecting them mutually so as to eliminate the need for a common line switching control circuit. CONSTITUTION:The control input (c) of a transmission line monitoring circuit 1 placed at a head of series connection is always fixed to the input presence state. When the transmission line monitoring circuit 1 monitors an input signal a1, the alarming signal d1 is outputted and when an output control input signal (c) is present thereon, the output of the alarming signal from (n) transmission line monitoring circuit outputting the transmission line signal b1 and the input of the output control are connected in series. Thus, (n) outputs are multiply connected.</p> |
