| 摘要 |
PURPOSE:To attain the switching of a low-speed line without using a switching device, by providing a low-speed line corresponding section and a high speed line controlling section, dividing the former into two blocks, and providing a switch and a selection circuit selecting which block is to be used. CONSTITUTION:In multiplex concentrators TDMs 3, 10, 3' and 10', the low- speed line corresponding sections are demoted by four groups E, F, G and H. The groups E, F at the center are connected to line groups A, B and only one of the groups E, F is connected to a high-speed line with the high-speed controlling section 10. The same operation is applied to the G, H at the terminal. Thus, the line groups A, B and C, D are connected mutually. The connection of the line corresponding sections E, F, G and H to a high-speed line is done by both TDMs independently. The high-speed controlling sections 10, 10' transmit a selection signal to the low-speed line corresponding section at each channel for the transmission and reception of data to a high-speed MODEM and select the low-speed line corresponding section. When a group changeover switch of the corresponding section selects the F at the center, the high-speed controlling section 10 connects it to the high speed line. The same operation is applied to the control at the terminal side also. |
