| 摘要 |
PURPOSE:To secure subscriber mutual communications stored in the same slave station even for break of communication, by providing the monitor circuit, which detects the disconnection state of the PCM line, and an intra-office folding connection device in the slave station, in the digital exchange system where slave stations and the master station are connected. CONSTITUTION:Various signals transmitted from or received by subscriber SL are converted to digital signals by line concentrating device SC and are transferred to the master station through the idle time slot of PCM highway HW by the control of control processing device RLNP and line concentration control device SCC. If the transmission line is faulty to break the communication with the master station, the fault of the transmission line is detected by transmission terminal station interface device TIF, and highway HW input and output to line concentrating device SC is connected to intraoffice folding connection device IOE by change-over switch SW to perform mutual connection in the slave station. |
