| 摘要 |
PURPOSE:To perform transmission in both directions after multiplexing a sub signal on a main signal with a spare system, by providing sub signal transmission lines with two channels in an up and a down directions, and forming a loop-shaped sub signal transmission line by connecting both ends of each one channel of the lines in the up and down directions at a connecting transmission line. CONSTITUTION:A system is constituted so that the time divisional multiplex of a sub data signal with two channels can be applied on an up main data signal transmitted on a digital transmission line in the up direction, and the sub signal transmission lines 11 and 12 are set by assuming respective channel as the sub signal transmission line in one up direction. Similarly, the sub signal transmission lines 21 and 22 in the down direction are provided. Between slave stations A and F, the connecting transmission lines capable of performing one channel transmission of the sub data signal are provided in both directions respectively, and the sub signal transmission lines 12 and 22 are formed in loop shapes respectively by those connecting transmission lines. When the digital transmission line in the up direction is disconnected between certain stations, the sub signal transmission lines 11 and 12 between those stations are disconnected. In such a case, the sub data signal in the up direction is transmitted on the sub signal transmission line 22 in the down direction, and the sub data signal in the down direction is transmitted on the sub signal transmission line 22 in the up direction.
|
